Using the James Webb Space Telescope, researchers applied a new technique called 3D eclipse mapping, or spectroscopic eclipse mapping, to track subtle changes in various light wavelengths as WASP-18b moved behind its star. These variations allowed scientists to reconstruct temperature across latitudes, longitudes and altitudes, revealing distinct temperature zones throughout the planet's atmosphere.

"If you build a map at a wavelength that water absorbs, you'll see the water deck in the atmosphere, whereas a wavelength that water does not absorb will probe deeper," Ryan Challener, a postdoctoral associate in Cornell’s Department of Astronomy and lead author of a study published on the research, said in a statement. "If you put those together, you can get a 3D map of the temperatures in this atmosphere."

WASP-18b is located about 400 light-years from Earth; it has roughly 10 times Jupiter's mass and completes an orbit of its host star in just 23 hours. Because it's so close to its star, temperatures in the planet's atmosphere reach nearly 5,000 degrees Fahrenheit (2,760 degrees Celsius). Those scorching conditions made it an ideal candidate for testing the new method of 3D temperature mapping.

The map revealed a bright central hotspot surrounded by a cooler ring on the planet's dayside — it has a tidally locked orbit, meaning that one side of the planet is always facing its star — demonstrating that the exoplanet's winds fail to distribute heat evenly across the atmosphere.

Remarkably, the hotspot showed lower water vapor levels than WASP-18b's atmospheric average. "We think that's evidence that the planet is so hot in this region that it's starting to break down the water," Challener said. "That had been predicted by theory, but it’s really exciting to actually see this with real observations."

This new 3D eclipse mapping technique will open many doors in exoplanet observations, as it "allows us to image exoplanets that we can't see directly, because their host stars are too bright," said Challener. As 3D eclipse mapping is applied to other exoplanets observed by Webb, "[w]e can start to understand exoplanets in 3D as a population, which is very exciting," he added.

The team's research was published in the journal Nature Astronomy on October 28, 2025.

It has previously been theorized that binary systems are hostile to the formation of complex planetary arrangements, meaning this discovery could change how we think about planet formation and the stability of worlds after formation. What makes the planets of TOI-2267 even more exciting is they also break some previously held exoplanet records.

Furthermore, the binary star nature of this system, located around 190 light-years from Earth, means these exoplanets could experience dual starsets reminiscent of the famous scene in Star Wars: A New Hope in which Luke Skywalker gazes dreamily out at the stars of his homeworld, Tatooine.

"Our analysis shows a unique planetary arrangement: two planets are transiting one star, and the third is transiting its companion star," Sebastián Zúñiga-Fernánde, study team member and a researcher at the University of Liège (ULiège), said in a statement.

"This makes TOI-2267 the first binary system known to host transiting planets around both of its stars."

Record breakers!

Binary star systems come in a range of shapes, sizes and arrangements. TOI-2267 is a "compact binary." This means the stars that comprise this system orbit each other in close proximity. This closeness causes gravitational instability that existing planetary formation models have suggested should result in an environment unsuitable for planet formation.

Yet, planets have formed in TOI-2267.

"Our discovery breaks several records, as it is the most compact and coldest pair of stars with planets known, and it is also the first in which planets have been recorded transiting around both components," Francisco J. Pozuelos, study team co-leader and a researcher at the Instituto de Astrofísica de Andalucía (IAA-CSIC), said in a statement.

Pozuelos and colleagues got their first hints about these three distant Earth-like worlds when they examined data from TESS using their detection software, SHERLOCK. This early indication of planets in the TOI-2267 system prompted the team to get ready for more observations with several other observatories. This included SPECULOOS, a network of robotic telescopes comprised of SPECULOOS Southern Observatory at the Paranal Observatory in Chile and SPECULOOS Northern Observatory at the Teide Observatory in Tenerife, and a pair of telescopes in Belgium called TRAPPIST (Transiting Planets and Planetesimals Small Telescope).

These facilities are specially adapted to investigate small exoplanets around cool and faint stars, meaning they were vital in allowing the team to characterize TOI-2267, and thus, discovering its surprising nature.

"This system is a true natural laboratory for understanding how rocky planets can emerge and survive under extreme dynamical conditions, where we previously thought their stability would be compromised," Pozuelos said.

The queries raised regarding planet formation by this system could be an investigation that is right in the wheelhouse of the James Webb Space Telescope (JWST) as well as the next generation of ground-based observatories. These instruments should allow astronomers to precisely measure the masses, densities and possibly even the atmospheric chemistry of the newly discovered planets of TOI-2267.

"Discovering three Earth-sized planets in such a compact binary system is a unique opportunity," Zúñiga-Fernández concluded. "It allows us to test the limits of planet formation models in complex environments and to better understand the diversity of possible planetary architectures in our galaxy."

The team's research was published on Friday (Oct. 24) in the journal Astronomy & Astrophysics.

The planet, known as GJ 251c, orbits a red dwarf star 18.2 light-years away in the constellation of Gemini, the Twins. The planet's mass is four times greater than that of Earth, making it a 'super-Earth' — a rocky planet larger and more massive than our own.

"While we can't yet confirm the presence of an atmosphere or life on GJ 251c, the planet represents a promising target for future exploration," said Suvrath Mahadevan, who is a professor of astronomy at Penn State University, said in a statement.

In the habitable zone, sometimes referred to as the Goldilocks zone, conditions are just right for liquid water to exist on the surface of a planet with an appropriate atmosphere.

GJ 251c was discovered thanks to observations spanning over 20 years, during which scientists looked for a slight wobble of the world's parent star incurred by the planet's gravity. As the star wobbles ever so slightly toward and away from us, we see a Doppler shift in its radial velocity that can be measured with a spectrograph.

One other planet is known to exist in the system, GJ 251b, which was discovered in 2020 and orbits its star every 14 days at a distance of 7.6 million miles (12.2 million kilometers). Using archive data from telescopes worldwide, a team of astronomers, including Mahadevan, was able to refine the accuracy of the radial velocity measurements for planet GJ 251b

The team then combined this refined data with brand new, high-precision observations from the Habitable-Zone Planet Finder (HPF), which is a near-infrared spectrograph on the Hobby-Eberly Telescope at McDonald Observatory in Texas. This revealed a second planetary signal belonging to a four-Earth-mass world orbiting the star every 54 days. That was then confirmed by measurements with the NEID spectrograph on the 3.5-meter WIYN telescope at Kitt Peak National Observatory in Arizona.

Though it may sound straightforward, in reality, the challenge of detecting the planet was formidable.

Stars are constantly roiling and churning as convective bubbles burst through to their visible surfaces and prominences splutter into space. This creates a noisy background of what's called asteroseismic activity that manifests as Doppler shifted lines in the star's spectrum. Picking out the Doppler shifted radial velocity signals from this noise is tricky, requiring a great deal of modeling what a planetary signal should look like.

"This is a hard game in terms of trying to beat down stellar activity as well as measuring its subtle signals, teasing out slight signals from what is essentially this frothing, magnetospheric cauldron of a star-surface," said Mahadevan.

Now that we know about the planet, astronomers can plan future observations.

GJ 251c is probably a little bit too far away from its star for the James Webb Space Telescope (JWST) to search for signs of an atmosphere around it. The next generation of 30-meter-class telescopes might be able to detect the planet's atmosphere via a method of searching for light reflected off its surface or atmosphere, but it will likely require the Habitable Worlds Observatory, which is a planned giant space telescope that is hoped to launch in the 2040s, to fully characterize GJ 251c.

"We are at the cutting edge of technology and analysis with this system," said Corey Beard of the University of California, Irvine, who participated in the research. "We need the next generation of telescopes to directly image this candidate."

Although GJ 251c is described by Mahadevan as being "one of the best candidates in the search for an atmospheric signature of life," referencing how we will search for biosignatures in the planet's atmosphere, there remains an elephant in the room: its star.

At 36% of the mass of our sun, the star GJ 251 is a red dwarf. Astronomers have now found numerous rocky planets in the habitable zone of red dwarfs, including Proxima Centauri b, TRAPPIST-1e and f, and Teegarden's Star b. However, red dwarfs are notorious for having violent tempers that bely their diminutive stature, releasing regular powerful flares that can over time strip a planet of its atmosphere. For example, the JWST's observations of the inner three planets of TRAPPIST-1 find no evidence for an atmosphere, while its observations of the fourth planet, e, are so far inconclusive. Some astronomers are now growing skeptical that Earth-like worlds can thrive around red dwarfs.

What GJ 251c has going for it is that it is slightly farther away from its star than habitable zone planets found around other red dwarfs are. This is thanks to its star being a little more massive than those other stars and therefore hotter, pushing the habitable zone farther out. It is possible that GJ 251c is far enough away from its star to have avoided the worst of its temper tantrums, and, if armed with a thick atmosphere and strong planetary magnetic field, it could have resisted the star's stellar wind from stripping its atmosphere away.

However, at present, this remains guesswork. "We made an exciting discovery," said Mahadevan, "But there’s still much more to learn about this planet."

The findings were reported on Oct. 23 in The Astronomical Journal.

Scientists spotted the heavy water (which we'll get into in just a moment) in the planet-forming disk of gas and dust around the young star V883 Orionis by ALMA, the Atacama Large Millimeter/submillimeter Array, which is a network of 66 radio dishes in Chile. V883 Ori is located 1,350 light-years away and is a member of a cluster of stars born out of the famous Orion Nebula.

Now, here's what heavy water is.

Ordinary water is formed of two atoms of hydrogen and one atom of oxygen. Hydrogen is made from a single proton orbited by an electron. However, the nuclei of some atoms of hydrogen feature one proton and one neutron, too. We describe atoms with extra neutrons as an isotope of that element, and the isotope of hydrogen with one neutron is called deuterium. Its atomic mass is slightly higher than regular hydrogen, thanks to that extra neutron.

Heavy water, therefore, supplants its two regular hydrogen atoms with two deuterium atoms. We have heavy water in our own solar system, found for example in comets — and the ratio of heavy water to ordinary water in a cometary body can tell us about its formation history.

"Until now, we weren't sure if most of the water in comets and planets formed fresh in young disks like V8783 Ori, or if it is pristine, originating from ancient interstellar clouds," said John Tobin of the National Radio Astronomy Observatory in the United States in a statement.

The ALMA observations provided the answer. Violent shocks and outbursts from young stars destroys heavy water in a planet-forming disk, allowing it to reform as regular water. If this had happened around V883 Ori, the ratio of heavy water to regular water would be low, similar to what we find in our solar system.

Instead, however, the ratio as measured by ALMA in V883 Ori's disk is the same as what is observed in clumps of molecular gas before they have formed stars or planets. In fact, the ratio is two orders of magnitude higher than what it would be if the water had been broken apart and reformed in the disk.

"Our detection indisputably demonstrates that the water seen in this planet-forming disk must be older than the central star and formed at the earliest stages of star- and planet-formation," said Margot Leemker, of the University of Milan, who led the study. "This presents a major breakthrough in understanding the journey of water through planet formation, and how this water made its way to our solar system and possibly Earth, through similar processes."

This means the water is older than the star — it could actually be billions of years older, having sat in the molecular cloud that became the Orion Nebula all that time as ice coating tiny dust grains.

V883 Ori is only half a million years old, and water was first detected in its circumstellar planet-forming disk in 2023. No planets have yet been detected in that disk, although any comets that may have formed already will mirror this high ratio of heavy water. The star's young age means there hasn’t been enough time yet for its ancient water to have been reprocessed by heating in the disk, but that time will soon come, as outbursts from the young star have already been observed — for example, in 2016, when ALMA studied the outburst's effect on the snow line, or where water turns from vapor to ice, in V883 Ori’s disk.

"The detection of heavy water … proves the water's ancient heritage and provides a missing link between clouds, disks, comets and ultimately planets," said Tobin. "This finding is the first direct evidence of water’s interstellar journey from clouds to the materials that form planetary systems — unchanged and intact."

The results were published on Oct. 15 in the journal Nature Astronomy.

The Mauve telescope, developed by London-headquartered start-up Blue Skies Space, is the size of a small suitcase and carries an off-the-shelf ultraviolet spectrometer modified to monitor flaring stars. It is one of the payloads that will launch on SpaceX's upcoming Transporter-15 mission, currently set for no earlier than November 2025.

Just like our sun, other stars in the universe produce flares — flashes of high-energy radiation from the dark, magnetically dense regions known as sunspots. Each flare sends a wave of energetic particles into the star's surroundings. When such a wave washes over Earth, the radiation, consisting of X-ray and extreme ultraviolet light, interferes with radio transmissions, causing blackouts. The flare also disturbs the ionosphere — the electrically charged layer of Earth's atmosphere at altitudes above 20 miles. This interference affects the accuracy of the navigation and positioning signal from satellites such as the U.S. GPS system.

But the sun is not a very active star. Research suggests that many of its siblings are much more temperamental. The bursts of radiation that some stars produce are so intense and so frequent that they virtually sear any object in their vicinity, preventing any possible life from emerging. By tracking the flaring of hundreds of stars, Mauve will help astronomers pick out those that are more likely to host habitable exoplanets.

"Mauve will allow us to understand the behavior of stars when they are emitting large amounts of energy," Marcell Tessenyi, the founder and CEO of Blue Skies Space, told Space.com. "It will also help us understand what sort of impacts these stars might have on their neighboring planets. We will be able to understand which stars are likely to be damaging for a life environment and which would be benign."

The last dedicated mission to observe stellar ultraviolet light, the International Ultraviolet Explorer, ended in 1996. The legendary Hubble Space Telescope can perform such measurements, but availability of observing time is limited, Tessenyi said. Hundreds of science teams from all over the world compete for observing time on the veteran space telescope, pursuing a multitude of challenging astronomical research projects that can't be accomplished by any other star-watching machine.

Since scientific interest in exoplanets is on the rise, Blue Skies Space decided to cover the increasing demand for observations of stellar flares with a small, low-cost telescope and sell the resulting data to scientists worldwide through a yearly subscription model.

"The space agencies do a fantastic job at delivering very high-quality space telescopes, but sometimes it can take a long time," Tessenyi said. "And when these satellites are operational, like the Hubble Space Telescope or James Webb, people have to apply and hope they get the observing time they need. But not all science requires a very large and complicated satellite."

With the low-cost Mauve (the company refused to disclose the exact cost of the mission), Blue Skies Space is pioneering a new approach to astronomical research from space. Although the new commercial space ethos of building satellites fast and cheap has dominated Earth imaging from space for years, deep-space astronomy has so far been headed mostly in the opposite direction — trending toward more complex machines worth billions of dollars.

Mauve, built in less than three years, is Blue Skies Space's first satellite to launch, although it was conceived after another mission, called Twinkle, which is still in the works. Twinkle, expected to make it to space later this decade, is a larger satellite, weighing 330 pounds (150 kilograms in mass) and carrying an 18-inch (45 cm) telescope. Like Mauve, Twinkle will look for exoplanets around nearby stars and gather information about their chemical composition. But Mauve, Tessenyi said, will help the researchers zoom in on the most promising stellar systems, to make Twinkle's work easier.

Tessenyi said that despite initial scepticism among scientists whether the new space way could work for astronomy, Blue Skies Space has seen a lot of interest in both of their missions. Nineteen universities from all over the world have already signed up for the data, which will begin streaming to Earth early next year.

Mauve will orbit Earth at an altitude of 310 miles (500 kilometers) for at least three years. If the project is successful, Blue Skies Space might add more satellites to its fleet in the future. The company is already studying a concept of a successor to Mauve, a more potent UV-observer Mauve+.

"We finance the satellites upfront, put them into space, and once the mission is operational, we make data available to users and over time we recover the cost of the construction and operations," Tessenyi said. "If the satellite is a success and we make a surplus, we reinvest that into our subsequent satellites and we grow the company to deliver more satellites using this model."

This strange world, which sits about 578 light-years from the solar system, breaks almost every known rule for how planets should behave. First off, it orbits a very young star that's just 700 million years old, making it one of the youngest planetary systems ever discovered. The planet is 9x wider than Earth, but only 30 times its mass. That means it's as wide as Jupiter but less than a tenth of its mass, a very light planet. This odd combination of large size and small mass classifies TOI-4507 b as a "super-puff" — an exoplanet with a large, extended atmosphere.

Second, TOI-4507 b is on a nearly polar orbit; it swings around its star almost perfectly perpendicular to the star's rotation. It has a relatively close orbit, completing an entire revolution in just 105 days — but this also makes it one of the longest-period super-puffs ever found. So we have a low-density, puffy planet orbiting relatively far from a young star in a nearly perpendicular orbit. What's going on?

With TOI-4507 b, there are more mysteries than answers. But the researchers who revealed the discovery of the planet ruled out some possibilities. In a pre-print study that has yet to be peer-reviewed and submitted to arXiv, they used a combination of data from NASA's Transiting Exoplanet Survey Satellite and ASTEP, a planet-hunting telescope in Antarctica.

Many super-puffs get their inflated atmospheres from tidal heating. If a planet orbits close to its star in an elliptical orbit, then its interior will stretch and squeeze as the gravitational strength of the star changes. This kind of tidal heating leads to the molten cores and liquid oceans of many moons in the outer solar system, and in other systems, it can heat up a planet, giving it an extended atmosphere.

But TOI-4507 b is too far from its star for tidal heating to play a significant role.

So perhaps it's not as big as we think it is. Some planets may have large ring systems that block light just as easily as a planet can, leading to the appearance of large planetary bodies. But while TOI-4507 b is relatively cold, it's not cold enough to support a ring system for very long.

Plus, something dramatic must have happened in this planet's past. This event might have been quick and catastrophic, causing a misalignment of the protoplanetary disk with the star. Or it might have been slow and steady — for example, if another planet orbiting much farther out were tugging it into a new orbit.

All of these mysteries make TOI-4507 b ripe for follow-up studies. Because of its brightness and the low density of its atmosphere, TOI-4507 b makes a great candidate for observations with the James Webb Space Telescope, which should have the capabilities to determine what this mysterious planet's atmosphere is made of — and hopefully unlock some more clues as to how this strange super-puff came to be.

The problem with Uranus and Neptune is that we have extremely little data available to us. Unlike Jupiter and Saturn, both of which have received dedicated missions like the Cassini probe and the Juno spacecraft, the outer planets have not received any visitors since the Voyager 2 flybys more than 30 years ago.

So, to build an understanding of these planets' interiors, we must rely on a variety of indirect clues, like their magnetic fields, observations of surface atmosphere features, and subtle changes in the orbits of their moons. For decades, models of solar system formation dictated that the outer realms of the solar system were dominated by molecules like water and ammonia ice. So naturally, those compounds would make up the bulk of Uranus and Neptune, hence their "ice giant" moniker.

But a new pre-print study accepted for publication in the journal Astronomy and Astrophysics took a completely different approach. Instead of trying to build a physical model of planetary interiors from possibly flawed and biased assumptions, the authors generated a series of random models of the interior contents of Uranus and Neptune. Then, they compared those random models to a host of observational data and built a database of all models compatible with observations.

The models yielded a few expected results. Each planet is less than a quarter hydrogen and helium, which matches predictions from solar system formation models and the observed densities of the planets. The models also created layers of electrically conductive material, which can explain the magnetic fields of Uranus and Neptune.

But this agnostic approach did yield one major surprise: We may not have any idea what the interiors of Uranus and Neptune are really like.

For example, the rock-to-water ratio for Uranus varies widely, anywhere from a low of 0.04, meaning the planet is almost entirely water, to as much as 3.92, which is the complete opposite. Neptune is slightly better understood, but it could still have anywhere from as much as five times as much water as rock up to twice as much rock as water.

If that's the case, then "ice giants" may be the wrong name for these planets. Most of their bulk could be in the form of rock, potentially giving them more rocky material than even Jupiter or Saturn, even though Neptune and Uranus are much smaller than those two gas giants.

If this idea holds up, it could challenge existing models of solar system formation, as we would have to figure out a way to get enough rocky material into the outer solar system to let it accumulate onto these planets.

Only a dedicated mission to Uranus or Neptune could resolve these issues, as we need high-quality data from an orbiter to fully understand what's going on.

Using the Magellan Telescope in Chile and the Large Binocular Telescope in Arizona, astronomers have captured a striking new view of a protoplanet named WISPIT 2b — a gas giant in its infancy estimated to be about five times more massive than Jupiter and just five million years old. The baby planet can be seen within a ring-shaped gap in the dusty disk surrounding its young parent star, named WISPIT 2, as it gathers material to grow into a fully realized planet.

The new image marks the first direct evidence of a growing planet observed within the very ring gap that it's shaping, confirming a longstanding prediction of how gas giants form, according to a statement from NASA.

WISPIT 2b orbits a star about 437 light-years from Earth. The disk of gas and dust, or "protoplanetary disk," that surrounds a young star functions as the birthplace for new planets. It has been suggested that gaps or clearings within these disks can be created by growing planets as they scatter material outwards.

WISPIT 2b was first detected using the European Southern Observatory's Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (VLT-SPHERE) in northern Chile, which initially revealed ringlike bands and a conspicuous gap that hinted at the protoplanet's activity.

Now, using Magellan's MagAO-X extreme adaptive optics system, astronomers have detected the faint glow of H-alpha light — the spectral fingerprint of hydrogen gas heating up as it falls onto a forming planet. Meanwhile, observations from the Large Binocular Telescope's infrared cameras captured WISPIT 2b in the same spot, helping to confirm that the emission came from an actively accreting planet rather than another source, according to the statement.

In the recent image shared by NASA, the protoplanet WISPIT 2b is a small purple dot to the right of a bright white ring of dust surrounding the system's parent star. A fainter white ring outside of WISPIT 2b can also be seen.

The position of WISPIT 2b inside the disk's gap suggests that it is not merely passing through but shaping its surroundings, sweeping up material and pushing dust aside as it grows. Astronomers even spotted a faint second source in another, inner ring gap that could mark a sibling world in formation.

Their findings from MagAO-X were published Aug. 26 in The Astrophysical Journal Letters, alongside another study published the same day using observations from the VLT-SPHERE instrument.

"We've found 6,000 planets, but none of them are like Earth," said Aurora Kesseli, an astronomer at Caltech who works on NASA's Exoplanet Archive keeping a tally of the worlds already discovered, in an interview with Space.com. "So when people ask why we are still looking for exoplanets when we have found 6,000 of them, it's because we haven't found an Earth-like planet yet. But there are a lot of the upcoming missions that are really tuned-in to try and find something that actually looks like Earth."

Several new planet-finding missions are on the cusp of being launched. First to go into space will be the European Space Agency's PLATO (PLAnetary Transits and Oscillations of stars), currently set to launch in December 2026 on a mission to search for the transits of planets including rocky, Earth-sized worlds in the habitable zone of their star.

A year later, NASA's Nancy Grace Roman Space Telescope will blast off for the L2 Lagrange point alongside PLATO and the James Webb Space Telescope (JWST). Although a multi-purpose space telescope, it will hunt for planets made visible by gravitational microlensing.

Then, in 2028, the China National Space Administration plans to launch the Earth 2.0 mission, which will also head to the Lagrange 2 point to search for planetary transits of Earth-like planets around sun-like stars.

With all three missions on the go at the same, and with NASA's TESS (Transiting Exoplanet Survey Satellite) still in operation, there will soon be a flood of new exoplanet discoveries, and Kesseli and her colleagues at the Exoplanet Archive are going to have to figure out how to collate all the data.

"The challenge for the Archive is definitely going to be handling the sheer numbers of exoplanets still to come, from PLATO, from Earth 2.0, from NASA's Roman Space Telescope," she said. "We're expecting on the order of 100,000 transiting planet candidates from those missions."

While these will only be candidates that will need to be verified, either through statistical methods or by determining their mass via radial velocity measurements, the current total of 6,022 exoplanets (as of the beginning of October) will soon increase dramatically. In fact, it could increase by a few thousand by as early as the end of 2026. That's when scientists working on the European Space Agency's Gaia mission, which carefully measures the position and properties of a billion stars, will release their catalogue of exoplanet candidates discovered via a technique known as astrometry, which relates to the position and motion of stars.

"Their first delivery of exoplanets is going to be in December 2026, and they are expecting a few thousand candidates," said Kesseli of the impending Gaia findings.

In the radial-velocity detection technique, with which 51 Pegasi b, the first planet known to orbit a sun-like star, was found, astronomers measure the Doppler shift of a star's subtle motion towards and away from us as it revolves around a center of mass shared with its orbiting planet(s). With astrometry, instead of measuring the radial motion of a star, astronomers measure its tangential motion on the sky as it is pulled in different directions by orbiting planets.

"So far we have less than 10 planets that have been discovered by astrometry," said Kesseli. That's because the measurements are difficult to make, the tangential motion being rather small. Gaia, however, is the most sensitive astrometric survey ever performed and will dramatically increase the number of exoplanets found through astrometry. However, most of these planets are likely to be gas giants, since less massive planets will have less gravitational pull on their star, leading to a much smaller tangential motion.

More sensitive to Earth-like worlds will be the Roman Space Telescope. Its 2.4-meter mirror is equipped to conduct wide-field surveys as opposed to the narrow field of view of the similarly sized but differently shaped mirror of the Hubble Space Telescope. As it gazes towards the center of our Milky Way galaxy, Roman will see countless stars in its field of view, enough to even the odds of seeing a microlensing event.

Microlensing is gravitational lensing on a small scale. We're used to seeing the arcs and rings of light belonging to the distorted images of galaxies magnified and warped by the mass of a giant galaxy, or galaxy cluster. However, planets can also bend space enough to lens the light of background stars. The alignment has to be perfect to enable this, and that alignment is only maintained for a brief period, but by watching many millions of stars at the same time, Roman is expected to come up trumps.

"From Roman we are going to get around 2,000 microlensing planets," said Kesseli.

Unfortunately, we will be unable to follow up on these planets once the planet and background star have moved out of alignment from our point of view. Part of the reason is that the vast majority of these planets will be very distant. "They will be far away, in the galactic bulge," said Kesseli.

The main reason, though, is that at no point during the microlensing event do we actually see the planet, or even the star that it orbits, which will usually be too faint to be seen. All we will see is a background star brightening briefly as its light is lensed first by the foreground star and then by the planet accompanying that foreground star. The more massive the planet, the brighter the lensed star becomes, and the bigger the gap between the brightening caused by the foreground star and then by the planet, the farther out the planet must be from its star. Indeed, the technique is particularly sensitive to planets far from their star, including Earth-like planets in the habitable zone.

The microlensing events should provide some statistics of how abundant Earth-sized planets in the habitable zone of sun-like stars are. However, to learn more about such worlds, astronomers will need to find one closer to home so that they can target it with their telescopes.

"Exoplanet characterization and studying exoplanet atmospheres is what I'm most excited about," said Kesseli. In fact, studying the atmospheres of exoplanets via a method called transit spectroscopy is Kesseli's specialty. With this method, a telescope such as the JWST can detect a planet's atmosphere through the way that the light from its star passes through the atmosphere when the planet is transiting. Molecules in the atmosphere absorb some of the star's light at certain wavelengths, leaving a chemical fingerprint on the star's spectrum.

"In the late 2020s ARIEL [Atmosphere Remote-sensing Infrared Exoplanet Large-survey] is going to be launched, which is a European mission to do a census of exoplanet atmospheres," Kesseli continued. "It probably won't do Earth-like planets around sun-like stars, it will mostly be doing Neptune- and Jupiter-sized worlds, but we will get a uniform sample of a thousands planets, so we'll be able to understand what the range in atmospheric conditions looks like, but likely not for rocky planets."

The James Webb Space Telescope is able to study the atmosphere of some nearby habitable-zone planets, but these are orbiting red dwarf stars and not sun-like stars. Red dwarf stars are very different from our sun. They are much smaller and cooler, and their planetary systems are much closer in, leading to tidally locked worlds that always show the same hemisphere to their star. Red dwarfs are also prone to violently flaring and the outpouring of radiation from them can strip an atmosphere clean off a planet.

So far the JWST has searched for an atmosphere around a handful of these planets including some of the worlds belonging to the TRAPPIST-1 system. While no atmospheres around these rocky planets have been discovered so far, Kesseli is not down-hearted.

"So far with JWST it is inconclusive," she said. "With more data, better techniques, more hours on targets like this, I think that we will start to have an idea about which planets likely host atmospheres and which ones don't. But JWST is not going to be able to look at the atmosphere of an exoplanet around a sun-like star, it just doesn't have the sensitivity for that."

Kesseli doubts that even the forthcoming class of 30-meter scale ground-based observatories will be able to detect the atmosphere of an Earth-like planet around a sun-like star. "It's really hard to do Earth-like planets around sun-like stars unless you're doing direct light," she said.

Instead, a whole new telescope, one designed specifically for the job, is required.

"If we want to see an actual Earth-like planet around a sun-like star, the best thing is going to be the Habitable Worlds Observatory, which will be launched in the 2040s," said Kesseli.

The Habitable Worlds Observatory, or HabEx for short, is NASA's next planned space telescope, championed by the National Academy of Science's Decadal Survey. At minimum it would feature an eight-meter telescope mirror, larger than JWST's 6.5-meter mirror, and a coronagraph in the form of a star-shade to block out the light of the host star so that HabEx can see the planet directly. Any planet that it images will still look like a point of light, but the spectrum of that point of light could reveal whether the planet has oceans, continents, vegetation, animal life or even cities.

The first 30 years of exoplanet science focused on discovery and of finding as many planets of all different types as possible so that scientists could draw up statistics for how common each type of planet is. Think of it as a census. And while that process of discovery is going to continue, the next 30 years are going to move increasingly into characterization as we get closer to our stated goal of finding another Earth-like planet truly capable of supporting life.

Perhaps that discovery will come in about 30 years' time courtesy of HabEx, and in turn that could set the tone for the 30 years that follow that, as we continue to reconfigure Earth's, and our, place in the cosmos.

The discovery of 51 Pegasi b was a turning point in astronomical history. No longer were we confined to studying just the planets in our own solar system; there was an entire universe of planetary systems out there for us to explore.

"When the first exoplanet was discovered, I remember thinking that it was really cool, but also thinking, 'Duh! Like, of course there are planets out there!'" said Amanda Hendrix, the director of the Planetary Science Institute in Arizona, in an interview with Space.com.

That first exoplanet proved to be the vanguard for an entire galaxy stuffed to the brim with planets. Today, the exoplanet count stands at more than 6,000 and is growing all the time. The statistics suggest that almost every star of the approximately 200 billion stars in our Milky Way galaxy has planets.

That means there are a lot of planets out there, but 51 Pegasi b was the first. Like most exoplanets, it was found indirectly. Astronomers Michel Mayor and Didier Queloz of the University of Geneva had been searching for planetary systems with ELODIE, a spectrograph on the 1.9-meter (6.2 feet) telescope at the Observatoire de Haute-Provence in France. ELODIE worked by being able to detect a star wobbling.

Why would a planet make a star wobble? Imagine a parent and child sitting on opposite ends of a long seesaw. The parent, being larger, has most of the mass, and the center of the combined mass of both parent and child is therefore much closer to the parent. That's why, with parent and child at either end, the seesaw tips in the direction of the adult.

Suppose, though, that they want to make the seesaw balance horizontally. The parent would shift themselves closer to the pivot point, moving the center of mass closer to the pivot. Once the center of their combined mass falls onto the pivot, the seesaw balances.

This is, in effect, what we see in exoplanetary systems. Just as in the example of the seesaw, the star is located very close to the center of mass because it contains the vast majority of the mass in the system. Often, the center of mass is inside the star, but crucially it is offset and not at its center.

The planet doesn't really orbit the star; it is orbiting the center of mass instead. And vice versa: The star also orbits the center of mass, so it appears to wobble around this point, and in doing so, it will periodically shift closer to us and then away from us. This movement is marginal, but it results in a Doppler shift in the star's light — as the star swings in our direction, its light waves bunch up, shortening their wavelength, and when it swings away from us, the light waves are more stretched out. It's the same effect as in the case of sound waves that change in pitch as they blare out from the siren of a passing emergency vehicle. The more massive the planet and the closer it is to its star, the stronger the shift.

Mayor and Queloz discovered 51 Pegasi b by using ELODIE to measure the Doppler shift in its star's light as it wobbled around the centre of mass between it and 51 Pegasi b. Astronomers call this technique the "radial velocity" method because it is measuring the velocity of the star toward and away from us as it wobbles around. Hundreds of planets have been found by this method since, and the existence of thousands more verified through it. So far, no direct image of 51 Pegasi b has been taken; the planet is too far away from Earth (50 light-years) and too close to its star to be seen by even our best telescopes.

Yet there was a twist. Mayor and Queloz had been expecting to find planetary systems with architectures like that of our solar system, with the smaller rocky planets closer to their star and larger gaseous worlds farther away.

So it was a shock when the size of the Doppler shift suggested that 51 Pegasi b is a gas giant practically on the doorstep of its star. It's a kind of planet that we now call a "hot Jupiter," but at the time it left astronomers flummoxed as to how such a remarkable planet could exist. According to models of planetary formation, gas giants couldn't form close to their star. It is a mystery that has since been solved: 51 Pegasi b and other hot Jupiter exoplanets formed farther from their star, but they then migrated toward the star to arrive in their current close orbit.

For Don Pollacco, who is the lead scientist on the European Space Agency's forthcoming planet-finding PLATO mission and a professor of astronomy at the University of Warwick in England, the discovery of 51 Pegasi b is an example of the dangers lurking in allowing our assumptions and scientific biases to blind us to reality.

"Trying to use our Earth and solar system as the example of what exoplanets should be like led to a big surprise," he told Space.com. "The first planets that were discovered were nothing like the planets in our solar system!"

The discovery of the first exoplanet around a sun-like star did not happen by accident. It was a race that Mayor and Queloz won. In second place was a group led by Paul Butler and Geoff Marcy, then at the University of California, Berkeley, who despite not making the first discovery were able to confirm the existence of 51 Pegasi b, which was important for getting the astronomical community to accept such an extraordinary find. Then, in 1996, Butler and Marcy found 70 Virginis b, which was the second exoplanet to be discovered orbiting a sun-like star and was another hot Jupiter.

Although the nature of 51 Pegasi b blew astronomers' minds, the fact that there were exoplanets at all was less shocking. Science fiction has, of course, been portraying exoplanets for decades, and in 1992, radio astronomers Dale Frail and Aleksander Wolszczan discovered planets orbiting a pulsar, the spinning remnant of a massive star that has gone supernova. However, many astronomers more or less dismiss pulsar planets — Pollacco describes them as "freakish" — because they are not thought to have formed like regular planets and are unlikely to be habitable.

For Hendrix, the key to finally discovering exoplanets was in developing instruments that were sensitive enough to detect them.

"It was just a matter of time before we found them," said Hendrix. "I don't want to diminish the excitement of it, but finding exoplanets really was expected; it was just a case of getting our technology up to speed to be able to find them."

For anybody under the age of 30, the concept of a universe in which we didn't know of other planetary systems might seem, pardon the pun, an alien one. Back in the late 1990s, however, it was like seeing science fiction come to life. The discovery of 51 Pegasi b changed the shape of astronomy. The young researchers inspired by that discovery are, today, leading the charge in discovering and characterizing thousands of exoplanets with some of the most expensive telescopes and space missions ever constructed.

"I remember going to two conferences, one after the other, in 1998," recalled Pollacco. "The first was on planetary nebulae, and I was the youngest person there. Straight afterwards I went to an exoplanet conference and I was the oldest person there! It was amazing, because in the planetary nebula conference there were about 60 people, and in the exoplanet one there were 300, so you could just see what was happening."

The wind had changed, and soon exoplanet science would grow into a monster scientific field, one that captures the imagination of astronomers and the public alike. Many types of world have been found, from more hot Jupiters to "mini Neptunes" and tidally locked worlds, to lava planets, super-Earths and worlds that stand a chance of being habitable, although to date no planet like Earth has been identified. That is a discovery that still lies in our future, and if and when it happens, the discoverers will join the names of Mayor and Queloz in the annals of history.

Rogue planets like this one are cosmic drifters — worlds that roam the galaxy untethered, unlike the familiar planets bound to a solar system. Most rogue planets are thought to be cold, silent wanderers. But Cha 1107-7626 is different.

"People may think of planets as quiet and stable worlds, but with this discovery we see that planetary-mass objects freely floating in space can be exciting places," Víctor Almendros-Abad, an astronomer at the Astronomical Observatory of Palermo, National Institute for Astrophysics (INAF), Italy and lead author of the new study in a statement.

For instance, Cha 1107-7626 is not just drifting through interstellar space — it's feeding.

Using the European Southern Observatory's (ESO) Very Large Telescope (VLT), astronomers have caught it pulling in gas and dust at an astonishing rate: six billion tons every single second. Never before has a rogue planet, or any planet, been observed growing this fast.

"This is the strongest accretion episode ever recorded for a planetary-mass object," Almendros-Abad said.

With a mass equivalent to between five and 10 Jupiters, Cha 1107-7626 is one of the lowest-mass free-floating planets known to host a disk and show active accretion. Observations from ESO's VLT and NASA's James Webb Space Telescope (JWST) reveal telltale signs of a rich, evolving system: infrared excess from 4 to 12 microns, silicate features at 10 microns (similar to those in stars and brown dwarfs), hydrocarbon emission lines pointing to a carbon-rich disk, and multiple signatures of ongoing accretion. Together, these make Cha 1107-7626 the clearest case yet of disk-driven growth in a planetary-mass object — a true poster child for how rogue planets can build themselves in the dark.

"The origin of rogue planets remains an open question: are they the lowest-mass objects formed like stars, or giant planets ejected from their birth systems?" wondered the study's co-author Aleks Scholz, an astronomer at the University of St. Andrews in the United Kingdom, in the statement.

Moreover, Cha 1107-7626 isn't growing at a steady pace — it surges. The team used VLT equipped with the X-shooter spectrograph, along with JWST data and archival observations from the VLT's SINFONI instrument, to catch the planet during a "growth spurt," or burst of accretion. By comparing the light it emitted before and during the burst, the team was able to piece together clues about the process.

Cha 1107-7626's violent growth spurt appears to have been fueled by its magnetic field, which is a process previously only observed in stars. Even more surprising, the chemistry of its disk shifted during the burst, with water vapor appearing only while the accretion was underway.

The discovery suggests at least some rogue planets may grow much like stars, since similar bursts of accretion have been seen in stellar nurseries. Detecting these free-floating worlds is notoriously difficult — they're faint and elusive — but that could soon change. With the upcoming Extremely Large Telescope (ELT), equipped with the world's largest mirror and operating under the darkest skies, astronomers will be able to track down more of these lone planets and reveal just how star-like they truly are.

"This discovery blurs the line between stars and planets and gives us a sneak peek into the earliest formation periods of rogue planets," Belinda Damian, an astronomer at the University of St. Andrews, said in the statement.

"The idea that a planetary object can behave like a star is awe-inspiring and invites us to wonder what worlds beyond our own could be like during their nascent stages," ESO astronomer Amelia Bayo said in the statement.

For years, scientists thought these planets, which are larger than Earth but smaller than Neptune, could form far from their stars, sweeping up ice beyond the so-called "snow line." As the planets migrated inward, scientists have thought that ice might melt into oceans hidden beneath hydrogen skies. Such hypothetical worlds were dubbed "Hycean planets," a blend of "hydrogen" and "ocean."

"Our calculations show that this scenario is not possible," Caroline Dorn, an assistant professor of Physics at ETH Zürich in Switzerland who co-led the new study, said in a statement.

The results come just months after high-profile claims about K2-18b, an exoplanet about 124 light-years away, made global headlines as a likely ocean world "teeming with life." A team of scientists studying James Webb Space Telescope (JWST) observations had reported hints of a possible biomarker gas, dimethyl sulfide, on K2-18b — fueling speculation that the planet might be cloaked in a hydrogen-rich atmosphere above a vast global ocean. These are conditions that could potentially support life (as we know it).

But those claims were quickly met with pushback. Independent analyses of the same JWST data suggested the team's evidence for DMS was weak at best, while other experts cautioned that sub-Neptunes may not be ocean-bearing worlds at all, but rather volatile-rich planets wrapped in thick, hostile atmospheres.

In the new study, Dorn and her team modeled how sub-Neptunes evolve during their early lifetimes, when they are thought to be blanketed by hydrogen gas and covered for millions of years by molten rock. Unlike earlier studies, the researchers included chemical interactions between magma and the atmosphere, according to the statement.

Of the 248 model planets the team studied, "there are no distant worlds with massive layers of water where water makes up around 50 percent of the planet's mass, as was previously thought," Dorn said in the statement. "Hycean worlds with 10-90 percent water are therefore very unlikely."

The team found that hydrogen and oxygen — the building blocks of H2O — tend to bind with metals and silicates in the interior, effectively sequestering water deep in the interior. Even planets that began with abundant ice ended up with less than 1.5% of their mass as water near the surface, the new study reports, far less than the tens of percent envisioned for Hycean planets.

"We focus on the major trends and can clearly see in the simulations that the planets have much less water than they originally accumulated," Aaron Werlen, a researcher on Dorn's team at ETH Zürich who co-led the new study, said in the same statement. "The water that actually remains on the surface as H2O is limited to a few per cent at most."

The researchers also found that the most water-rich atmospheres did not appear on planets formed far from their stars, where ice is plentiful, but rather on planets formed closer in. In these cases, water was generated chemically, as hydrogen in the atmosphere reacted with oxygen from the molten rock.

The implications are sobering for astrobiology. If Hycean planets do not exist, the most promising havens for liquid water, and potentially life, may lie on smaller, rocky worlds more akin to Earth.

Still, K2-18b remains a captivating target, scientists say. As a sub-Neptune, a type of planet missing from our own solar system but common across the galaxy, it could reveal fundamental insights into how planetary systems form and why ours turned out the way it did.

The new results also suggest that Earth may not be exceptional, with many distant worlds veiled in similarly modest traces of water.

"The Earth may not be as extraordinary as we think," Dorn said in the statement. "In our study, at least, it appears to be a typical planet."

The research was published on Sept. 18 in The Astrophysical Journal Letters.

The first planets studied by the ATREIDES program, the two worlds of the TOI-421 system, demonstrate misaligned orbits, hinting that this system experienced a more chaotic evolution than our solar system. Studying it could help astronomers figure out why these "hot Neptunes" appear to be so rare in the cosmos, as well as teach us about how planets form elsewhere in the universe.

"The complexity of the exo-Neptunian landscape provides a unique window onto the processes involved in the formation and evolution of planetary systems," ATREIDES Principal Investigator and University of Geneva (UNIGE) researcher Vincent Bourrier said in a statement describing the ATREIDES program.

To understand why this class of extrasolar planet, or "exoplanet," is missing from close orbits around other stars, ATREIDES scientists investigated the TOI-421 planetary system. Located around 244 light-years from Earth, TOI-421 is an orange dwarf or "K-type" star orbited by two exoplanets, TOI-421 b and TOI-421 c. What this investigation revealed is a surprisingly tilted orbital situation in TOI-421 that implies that this system experienced a chaotic history, one which may help explain why hot Neptunes are so rare.

TOI-421 b is a scorching hot sub-Neptune planet with a mass around 7 times that of Earth that orbits its star at a distance equivalent to around 6% of the distance between our planet and the sun. TOI-421 c is larger, with a mass of around 14 times that of Earth, which orbits its star at a distance equivalent to around 12% the distance between Earth and the sun, making it a hot Neptune and putting it in a region adjacent to the Neptunian desert called "the savanna."

"A thorough understanding of the mechanisms that shape the Neptunian desert, savanna, and ridge will provide a better understanding of planetary formation as a whole ... but it's a safe bet that the universe has other surprises in store for us, which will force us to develop new theories," Bourrier said.

Mapping the Neptunian desert

Over the last 10 years of exoplanet observations, the Neptunian desert has become increasingly complex. Areas further out from stars than the Neptunian desert have been found to be more generously populated with Neptune-sized worlds. This more temperate realm with more Neptune-like exoplanets has come to be known as the "savanna" of the Neptunian desert.

Astronomers have also defined a region between the Savanna and the Neptunian desert, which they call the "Neptunian ridge." This region is more densely populated by Neptune-like worlds than both the desert and the savanna. The scientists of the ATREIDES program aim to understand these three distinct regions by identifying the processes that lead to the relative planetary populations.

The team wants to test the hypothesis that the Neptunian landscape is created as a result of the way that planets migrate from their birthplaces to the orbits we observe them in.

Some exiled planets would migrate slowly through the disk of gas and dust that exists in these systems during their infancy. This sedate migration should produce planets in orbits aligned with their star's equator and the orbits of the other planets in their home system. That is similar to the orbits of the planets in the solar system, which are aligned almost to the equatorial plane of the sun.

However, some other planets would be violently thrown from their site of formation via a chaotic process called "high-eccentricity migration." That should result in those planets falling into highly misaligned orbits.

That means the alignment between a star's orbital plane and the orbital plane of its planets is key to investigating this migration hypothesis.

The team can't yet say anything conclusive yet about the Neptunian desert, its neighboring regions, or planetary evolution in general. Many more observations of more planetary systems with hot Neptunes will be needed for that.

However, this research successfully demonstrates the effectiveness of the ATREIDES program and the techniques it has developed and employed.

The team's research was published on Tuesday (Sept. 16) in the journal Astronomy & Astrophysics.

"We're entering the next great chapter of exploration — worlds beyond our imagination," a narrator says in a NASA video about the milestone. "To look for planets that could support life, to find our cosmic neighbors and to remind us the universe still holds worlds waiting to be found."

The news was announced on Wednesday (Sept. 17), which is serendipitously close to the anniversary of when scientists confirmed the existence of the first exoplanet around a sun-like star: 51 Pegasi b. Discovered on Oct. 6, 1995 by astronomers Michel Mayor and Didier Queloz, 51 Pegasi b is a gas giant 0.64 times as massive as Jupiter that sits approximately 50 light-years from where you're sitting. (To be clear, the very first exoplanet discovery fell in 1992, but that one was around a spinning neutron star, or pulsar. And pulsars are pretty wild. 51 Pegasi b was the first more "normal" exoplanet to be identified.) The right thing to do would be to end this paragraph with the 6,000 exoplanet discovery counterpart to 51 Pegasi b, but that's unfortunately not possible.

This brings us to the complexity of NASA's announcement. "Confirmed planets are added to the count on a rolling basis by scientists from around the world, so no single planet is considered the 6,000th entry," the agency said in a statement. "There are more than 8,000 additional candidate planets awaiting confirmation."

In fact, as of writing this article, we're technically at 6,007 exoplanets in NASA's alien world tally. The "new discovery" featured by NASA is the heftily named KMT-2023-BLG-1896L b, a Neptune-like world with a mass equal to about 16.35 Earths. NASA is also responsible for the bulk of those exoplanet finds, with its TESS (Transiting Exoplanet Survey Satellite) count being at 693 and now-retired Kepler Space Telescope having found over 2,600.

And even though it can be written with just a few keystrokes, each member of that 6,007-strong club represents an entire world comparable to the planets of our solar system, which scientists have been scrutinizing for centuries.

There are 2,035 Neptune-like worlds in that count, in reference to exoplanets with similar sizes to our solar system's very own Neptune and Uranus. These tend to have "hydrogen and helium-dominated atmospheres with cores of rock and heavier metals," according to NASA. ("Metals" doesn't necessarily mean metallic elements. Somewhat confusingly, in astronomy, that just refers to elements heavier than hydrogen and helium).

There are 1,984 gas giants (think Jupiter relatives) and 1,761 super-Earths in the court — the latter group is not to be confused with Earth 2.0 candidates. Super-Earths simply refer to exoplanets that are a little larger than Earth but still lighter than planets like Neptune and Uranus.

NASA's exoplanet count further includes 700 "terrestrial planets," or rocky worlds, and maybe most fascinatingly, seven of "unknown" types.

Indeed, breaking those categories down even further would require stretching your brain to a place where you can imagine a two-faced world half-covered in lava, an orb made of diamond that can regrow its atmosphere, one zipping through space at over 1 million mph (1.6 million kph) and the physical embodiment of hell.

"Each of the different types of planets we discover gives us information about the conditions under which planets can form and, ultimately, how common planets like Earth might be, and where we should be looking for them," Dawn Gelino, head of NASA's Exoplanet Exploration Program, located at the agency's Jet Propulsion Laboratory in Southern California, said in a statement. "If we want to find out if we’re alone in the universe, all of this knowledge is essential."

Still, in the agency's video about the milestone, an existential aspect of exoplanet-hunting is mentioned. "There's one we haven't found — a planet just like ours."

At least, not yet."

A new study presented by professor Susanne Pfalzner of Forschungszentrum Jülich at the Joint Meeting of the Europlanet Science Congress and the Division of Planetary Sciences last week suggests such interstellar objects could serve as "seeds" for exoplanet growth around young stars.

Planetary formation is believed to occur through a process called accretion — which involves small particles in dusty, gas-rich disks around young stars colliding and sticking together, gradually growing to the size of planets. But there's a bit of a blip in the story. Collisions between boulder-size objects should tend to cause them to bounce or shatter rather than merge.

Pfalzner's models show that interstellar objects — bodies ejected from other star systems — could be captured by these planet-forming disks. These objects could "seed" the disks, sweeping past the growth barrier by providing substantial mass onto which more material can accrete.

"Interstellar objects may be able to jump-start planet formation, in particular around higher-mass stars," Pfalzner said in a statement, noting that simulations predict millions of interstellar bodies could be captured per disk.

This discovery might also solve another mystery. Jupiter-like giant gas planets are most commonly found around more massive stars rather than smaller ones. But the protoplanetary disks around these massive stars only last around 2 million years before dispersing — and that's not quite enough time to create gas giants. But the arrival of interstellar objects into a massive star's disk might speed up the process.

"Higher-mass stars are more efficient in capturing interstellar objects in their disks," said Pfalzner. "Therefore, interstellar-object-seeded planet formation should be more efficient around these stars, providing a fast way to form giant planets. And, their fast formation is exactly what we have observed."

This summer's discovery of 3I/ATLAS — only the third confirmed interstellar object ever observed passing through our solar system, after 1I/'Oumuamua in 2017 and 2I/Borisov in 201— adds credence to this theory. Its detection suggests such objects may be far more common than previously thought, increasing the plausibility that young stars frequently acquire these alien building blocks.

Astronomers have discovered the secret of a strange star system that has baffled them for years, finding it contains a dead star about to erupt after overfeeding on a stellar companion. The supernova explosion of this cosmic cannibal could be as bright as the moon, making it visible with the naked eye over Earth even in broad daylight.

The system in question is the double star V Sagittae located around 10,000 light-years from Earth, containing a white dwarf stellar remnant and its victim companion star, which orbit each other roughly twice every Earth day. The new research and the revelation of this white dwarf's imminent catastrophic fate answer questions about V Sagittae that have lingered for 123 years!

"V Sagittae is no ordinary star system - it's the brightest of its kind and has baffled experts since it was first discovered in 1902," team member and University of Southampton researcher Phil Charles said in a statement. "Our study shows that this extreme brightness is down to the white dwarf sucking the life out of its companion star, using the accreted matter to turn it into a blazing inferno.

"It's a process so intense that it's going thermonuclear on the white dwarf's surface, shining like a beacon in the night sky."

Final fate of a cosmic cannibal

White dwarfs represent the final stage of stars with masses around that of the sun, occurring when they run out of fuel for nuclear fusion. Indeed, our star will end its life as a cooling white dwarf when it runs out of hydrogen in around 5 billion to 6 billion years.

While this smoldering cosmic ember state represents the end for single stars going out with a whimper rather than a bang, white dwarfs that have a stellar companion can get a second lease on life and a more conclusive and explosive end. This happens when its dense stellar corpse is close enough to its companion star to allow its gravity to begin stripping away the partner's stellar material.

This material can't fall straight to the white dwarf because it has angular momentum, or spin. That means it forms a swirling, flattened cloud of matter around the white dwarf called an accretion disk, which gradually dumps matter to its surface.

This situation continues, and the stolen stellar material piles up on the surface of the white dwarf until it pushes this stellar remnant past the so-called Chandrasekhar limit of 1.4 solar masses. This is the mass limit that a stellar remnant has to exceed to trigger a supernova. The result is a Type Ia supernova that usually completely destroys the greedy white dwarf star.

However, this team found something very different and extraordinary happening with the stellar material being stolen by the white dwarf in V Sagittae.

The team uncovered the violent nature of V Sagittae using the Very Large Telescope (VLT), comprised of four individual telescopes located almost 9,000 feet (2,636 meters) on Cerro Paranal in the Atacama Desert of northern Chile.

This investigation revealed that there is a giant halo of gas comprised of material stolen from the companion star wrapped around both the cannibal white dwarf and its stellar victim. This is the result of the incredible amount of energy being generated in the system by the white dwarf as it strips material from its companion star.

This vast system-wide gas halo indicates that the white dwarf is snatching way more matter than it can handle. It also implies that this situation isn't going to continue for long, though when the end will come for this white dwarf isn't quite certain.

"The white dwarf cannot consume all the mass being transferred from its hot star twin, so it creates this bright cosmic ring," team member Pasi Hakala from the University of Turku said. "The speed at which this doomed stellar system is lurching wildly, likely due to the extreme brightness, is a frantic sign of its imminent, violent end."

"The matter accumulating on the white dwarf is likely to produce a nova outburst in the coming years, during which V Sagittae would become visible with the naked eye," Pablo Rodríguez-Gil from Spain’s Instituto de Astrofisica de Canarias said. "But when the two stars finally smash into each other and explode, this would be a supernova explosion so bright it'll be visible from Earth even in the daytime."

The team's research was published on Thursday (Sept. 11) in the journal Monthly Notices of the Royal Astronomical Society.

Some are scorched giants hugging their suns, others are icy wanderers drifting in the dark. And then there are the tantalizing few that might resemble Earth, raising the ultimate question: could life exist out there?

From the groundbreaking Kepler mission to the latest data from the James Webb Space Telescope, you'll dive into the techniques astronomers use to detect these elusive worlds and decode their secrets.

The universe is teeming with planets waiting to be discovered, and this quiz is your chance to explore them. Will you prove yourself a true exoplanet explorer — or get lost in the interstellar shuffle?

Try it out below and see how well you score!

Every once in a while, you may look up towards the sun and see strange bright lights on either side of it. Or perhaps you’ll be sitting in an aircraft, looking out the window at its shadow and see a circle of light, like a halo below (known as glories). Or, if you’re really adventurous, maybe you’ll even be out on a midnight walk with a full moon lighting your way, and see what appears to be a rainbow encircling the moon.

These are all beautiful examples of atmospheric optical phenomena. And a new paper has suggested they may appear in alien skies too.

These celestial wonders can tell us a lot about the state of the atmosphere at home on Earth as well as on other planets. Rainbows, for instance, the most well-known of these phenomena, can only form when light passes through spherical liquid droplets, like our normal rain on Earth. Therefore, there must be spherical liquid droplets in the atmosphere where the rainbows are observed.

Most planet atmospheres have some kind of crystalline aerosols (clouds of tiny particles) in them, from sodium chloride in Io (one of Jupiter's moons), to carbon dioxide crystals in Mars. On Earth, these are generally ice crystals, often found in clouds as snowflakes. The orientation of these crystals, and how they change the light, dictates the type of optical phenomena you can see.

Sun dogs are another of these phenomena, where bright lights appear on either side of the Sun, sometimes even splitting white light into the colors of the rainbow. They form because of the light being bent by horizontally oriented hexagonal ice crystals high up in the atmosphere. If you want the best chance of seeing these, you should try to be at the same latitudes as Europe or Argentina during wintertime. Look for high altitude wispy clouds that are in front of the Sun, and you might get lucky.

Horizontal ice crystals can also create light pillars in extremely cold conditions, which look like colored beams of light trailing to clouds over head. Vertical crystals form parhelic circles – a circle of light at the same height as the Sun. And crystals aligned with the electric fields above thunderstorms create crown flashes.

The new paper proposes that, from what we know of our own atmosphere, we can presume that similar optical phenomena happen on planets outside of our solar system (called exoplanets). It’s just a matter of spotting them and finding out why they occur.

Previous studies have shown that on many exoplanets the crystalline aerosols in their atmospheres are moved around and oriented in a multitude of different ways, much like on Earth.

Magnetic fields swirl around the planet, as they do on Earth, pushing and pulling along field lines. On Earth, this can be seen as the northern lights phenomena. Radiation pressure from a planet's parent star pushes the crystals using the power of light, much like how the wind pushes boats. And the wind, often much faster than anywhere on Earth, speeds around the exoplanet, rushing from the hot, star-facing side of the exoplanet to the colder space-facing side as the planet spins.

A special type of exoplanet, hot Jupiters (so named because they’re huge, gassy and very hot) generally have incredibly fast winds (up to 18,000km/h) and high densities of crystalline aerosols, much like an incredibly fast-moving sandstorm.

This means that the main way that the crystals are oriented is through the superfast winds spinning around the planet. Imagine a fleet of boats all randomly turned around in a patch of ocean, then a massive gust of wind comes, turning them all so that they’re facing the same direction.

The researchers on the new paper previously used the James Webb Space Telescope (JWST) to find evidence for tiny quartz crystals in the high altitude clouds of a hot Jupiter 1,300 light years away from Earth (WASP-17 b). These crystals have an elongated shape, like boats, so are more likely to be oriented with the wind. This led them to think about what optical properties could be seen with the wind-aligned crystals.

The optical phenomena that come from the crystals being oriented the same way cannot be seen by normal cameras. But scientists can use instruments such as those on the JWST to observe these effects.

We have already gained valuable information about faraway atmospheres from looking at their optical phenomena using the JWST. For example on Venus, rainbows and glories have been used by scientists to decipher the mysteries of Venus' extreme heats and yellow color.

A similar technique of observing glories has been used to detect the presence of long-lasting clouds on the exoplanet WASP-76b. The new knowledge of these clouds gives us insight into the exoplanet's atmosphere. Now we know that there can be conditions for a stable temperature, which surprised scientists as half of the planet is hot enough to melt iron.

We can also guess what optical effects might occur on planets where we know what the atmosphere is made of. For example, in the high atmospheres of Jupiter and Saturn, where a special type of ammonia crystals are concentrated, we would expect to observe four separate sun dogs. Alas, on Earth, we can only ever see two at a time due to the shape of our atmospheric ice crystals.

Who knows what other wondrous phenomena we may see on other worlds. Who's to say whether there couldn't be a planet surrounded by continual rainbows? There is much more to learn about so many exoplanets. Optical phenomena such as sun dogs can tell us huge amounts about their atmospheres, which could help us in the search for habitable planets in the future.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Water ice molecules are among the most common in the cosmos and influence the interior and exterior of many planetary bodies in our solar system. Glaciers shape parts of Earth's surface, and dwarf planet Pluto, along with moons such as Europa, Ganymede, Titan, and Enceladus, have whole landscapes made up of ice alone, including boulders, mountains, and even volcanoes.

Under high-pressure or very low temperature conditions, ice forms different crystal structures than those that occur naturally on Earth. Identifying and measuring those structures on worlds such as Ganymede would provide unique data on the interiors of these celestial bodies, in the same way studying mantle rocks pushed to the surface on Earth reveals our planet’s deep geology.

In the lab, researchers can bombard ice with X-rays or neutrons to understand its structure. But such instruments aren’t practical to fly on spacecraft.

Now, new experiments conducted by Christina Tonauer and her colleagues at Universität Innsbruck in Austria show how to distinguish between ice structures using infrared spectroscopy. The analyses, published in Physical Review Letters earlier this summer, can be done using observations from NASA's James Webb Space Telescope (JWST) or the European Space Agency's JUICE (Jupiter Icy Moons Explorer) mission currently en route to Jupiter.

"The ices that we prepare in the lab only occur naturally in space," said Tonauer, whose work combines her field of physical chemistry with her love for planets. "I'm also really interested in astronomy, and this is what hooked me to water ice."

During Tonauer's Ph.D. work in the early 2020s, JWST was still to be launched, but it was clear the infrared observatory would open avenues for studying the ice-covered moons of the outer solar system. When she and her collaborators delved into the literature, they realized that a lot of spectroscopic work on ice—research that largely predated the leaps in understanding gained from the Voyager and Cassini missions—considered infrared (IR) wavelengths longer than those JWST could measure.

It seemed fruitful to Tonauer and her colleagues to study the shorter-wavelength IR spectrum (near-IR) emitted by ice on these distant worlds.

Ice maker, ice maker, make me some ice

As of 2025, 21 different phases of ice have been identified in laboratory experiments, although only one form exists under normal conditions on Earth. That form is called ice I_h (pronounced “ice one aitch”), where "h" refers to the hexagonal pattern the molecule's oxygen atoms take when viewed from one direction.

The conditions that allow researchers to study other ice phases in the lab exist naturally on other planets and moons, however, and scientists have concluded the phases might exist there.

Ganymede and other worlds in the outer solar system likely have something akin to mantle dynamics, for example, but with ice instead of silicate minerals.

Ganymede's mantle could be 800 kilometers thick and consist of several forms of ice that are known only from laboratory experiments on Earth. Tonauer and her collaborators selected ice V and ice XIII for their study, because they form under the high pressures and low temperatures present inside Ganymede and other moons. These phases have the same arrangement of oxygen atoms, but different orientations of hydrogen atoms: In ice V, hydrogen is jumbled around, whereas hydrogen in ice XIII is structured.

Making these types of ice in the lab requires cooling liquid water with liquid nitrogen under about 5,000 atmospheres (500 megapascals) of pressure. As long as the samples are kept cold after forming, Tonauer noted, they don't require high pressure to remain stable because the atoms move so slowly.

However, that slow motion still stretches the bonds between molecules, a vibration that produces IR signals. Using spectroscopy to interpret the emissions, Tonauer and her colleagues discovered that these signals are different for ice V and ice XIII. That difference provided the first experimental demonstration of using IR to distinguish hydrogen configurations within different phases of ice. It also highlighted a way to identify them remotely.

The researchers used a JWST simulator to show that a few hours of observation would be enough to distinguish between these ice phases on Ganymede.

A peek at deep ice

The stability of these ice phases is key to understanding their potential presence on the surface of Ganymede: The phases require high pressure to form, but if brought to the lower-pressure surface, they can maintain their exotic crystal structure indefinitely. In that way, the presence of ice V or XIII would provide details about the icy mantle that would otherwise be inaccessible.

Past and present missions to the Jovian system have clearly indicated that Ganymede's interior contains a liquid water ocean sandwiched between ice layers, but the ices' crystalline structures, as well as how the layers move and evolve, have not been verified by empirical data. According to models of icy moon interiors, the high-pressure environment should produce ice V, which phenomena such as the tidal force from Jupiter might bring to the surface.

These new infrared spectroscopy analyses show how to distinguish between ice I_h, ice V, and ice XIII—not to mention amorphous ice, which lacks a clear crystal structure—without having to return samples to Earth for laboratory analysis (a prohibitively expensive proposition). The method could provide an observational way to verify or refute models of interior ice dynamics, sharpen our picture of Ganymede's internal structure, and help us understand how different flavors of ice behave and interact with each other in a natural environment.

"We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return," said Danna Qasim, a laboratory astrophysicist at the Southwest Research Institute in Texas who was not involved with the new study.

Qasim pointed out that if the grains of these ices are small and jumbled together, it might be difficult to extract their IR signature. As other recent research has shown, amorphous ice in space likely contains chunks of crystalline ice joined together at odd angles, which also might make identification more difficult.

However, the new method seems promising and could well answer vital questions about the internal structure of icy moons.

"We invest billions of dollars in these spectacular space missions," Qasim said. "If we want to truly understand what the data is telling us about these enigmatic beautiful worlds, it is absolutely necessary to have laboratory experiments like the ones performed here."

The planet in question is TRAPPIST-1e, an Earth-sized rocky exoplanet that's located around 40 light-years away from our planet.

TRAPPIST-1e is the fourth planet in orbit around a red dwarf star called TRAPPIST-1. It sits well within the "habitable zone" or Goldilocks zone, the region of space around a star that is neither too hot nor too cold to allow liquid water to exist on the surface of a planet.

However, just existing in the habitable zone of a star isn't sufficient to guarantee the existence of liquid-water oceans or indeed the conditions needed to support life. After all, Earth, Mars, and Venus are all in our solar system's habitable zone, but only one of these planets has water oceans and supports life today (as far as we know). One of the key differences is the atmosphere of our planet, and that is what astronomers are searching for around TRAPPIST-1e.

"TRAPPIST-1e has long been considered one of the best habitable zone planets to search for an atmosphere," study team member Ryan MacDonald, a researcher at the University of St. Andrews in Scotland, said in a statement. "But when our observations came down in 2023, we quickly realized that the system’s red dwarf star was contaminating our data in ways that made the search for an atmosphere extremely challenging."

The JWST data indicate several possible scenarios for TRAPPIST-1e and its potential atmosphere. That makes this research a significant step forward in the search for life beyond the solar system.

To examine the potential atmosphere of TRAPPIST-1e, the team had to wait until it crossed or "transited" the face of its parent star. This reveals details of the chemical composition of a planet's atmosphere because chemicals absorb light at characteristic wavelengths. That means when starlight passes through a planetary atmosphere, the chemicals in that atmosphere leave their characteristic "fingerprints" in the spectrum.

This isn't as straightforward as it may initially sound. Astronomers have to account for factors like starspots across the face of the red dwarf star. So the team has spent the last year carefully removing contamination from the TRAPPIST-1e data to hone in on the planet's atmosphere, or lack thereof.

"We are seeing two possible explanations," MacDonald said. "The most exciting possibility is that TRAPPIST-1e could have a so-called secondary atmosphere containing heavy gases like nitrogen. But our initial observations cannot yet rule out a bare rock with no atmosphere."

The indeterminate nature of the team's results means that JWST is far from finished with TRAPPIST-1e. The researchers hope to perform a deeper search for the planet's atmosphere, with each subsequent transit potentially presenting a clearer picture of its atmospheric contents.

"In the coming years, we will go from four JWST observations of TRAPPIST-1e to nearly 20," MacDonald concluded. "We finally have the telescope and tools to search for habitable conditions in other star systems, which makes today one of the most exciting times for astronomy."

The team's research was published as two papers on Monday (Sept. 8) in The Astrophysical Journal Letters

The protoplanetary disk has an odd chemical composition. It features a surprisingly high concentration of carbon dioxide in the region in which rocky planets like Earth are expected to form and is also unexpectedly low in water content.

The protoplanetary disk investigated by JWST surrounds the infant star XUE 10, which is located around 5,550 light-years from Earth in the vast star-forming region known as NGC 6357. The new discovery was made by the eXtreme Ultraviolet Environments (XUE) collaboration, a research team that focuses on how intense fields of radiation impact the chemistry of protoplanetary disks.

"Unlike most nearby planet-forming disks, where water vapor dominates the inner regions, this disk is surprisingly rich in carbon dioxide," XUE collaboration team member Jenny Frediani, of Stockholm University in Sweden, said in a statement.

"In fact, water is so scarce in this system that it’s barely detectable — a dramatic contrast to what we typically observe," Frediani added. "This challenges current models of disk chemistry and evolution, since the high carbon dioxide levels relative to water cannot be easily explained by standard disk evolution processes."

Strange chemistry

Stars form when overdense patches clump together in vast clouds of gas and dust, eventually gathering enough mass to undergo gravitational collapse. What remains of the material that birthed this still-growing protostar swirls around it, flattening out and eventually forming a protoplanetary disk in which planets can be born.

Scientists currently theorize that planet formation occurs when "pebbles" rich in water ice drift from the colder outer regions of a protoplanetary disk to its warmer inner regions. These higher temperatures cause solid ice to transform directly into gas, a process known as sublimation.

This usually also results in telescopes like JWST spotting strong signals from water vapor in protoplanetary disks. The disk around XUE 10, however, showed strong carbon dioxide signals.

"Such a high abundance of carbon dioxide in the planet-forming zone is unexpected," said XUE Collaboration member and Stockholm University researcher Arjan Bik. "It points to the possibility that intense ultraviolet radiation — either from the host star or neighboring massive stars — is reshaping the chemistry of the disk."

This wasn't the only surprise that JWST delivered to the team with regard to XUE 10 and its protoplanetary disk. Data from the disk revealed molecules of carbon dioxide, enriched with the carbon isotopes carbon-13 and the oxygen isotopes oxygen-17 and oxygen-18.

The presence of these isotopes could help explain why certain unusual isotopes are left in fragments of the early solar system in the formation of meteorites and comets.

The research demonstrates JWST's impressive ability to detect chemical fingerprints in distant protoplanetary disks during crucial eras of planet formation.

"It reveals how extreme radiation environments — common in massive star-forming regions — can alter the building blocks of planets," said team leader Maria-Claudia Ramirez-Tannus from the Max Planck Institute for Astronomy in Germany. "Since most stars and likely most planets form in such regions, understanding these effects is essential for grasping the diversity of planetary atmospheres and their habitability potential."

The team's research was published on Friday (Aug. 29) in the journal Astronomy & Astrophysics.

WISPIT 2b is estimated to be a gas giant around the size of Jupiter and around just 5 million years old. If this seems ancient, remember our solar system is around 4.6 billion years old. The extrasolar planet, or "exoplanet," is carving a channel in the planet-forming disk of gas and dust, or "protoplanetary disk," around its young parent star WISPIT 2 like a cosmic Pac-Man as it gathers material.

The exoplanet is the first confirmed detection of a planet in a multi-ringed protoplanetary disk, a disk that contains multiple gaps and channels, almost akin to a vinyl record.

Imaged using the Very Large Telescope (VLT) located in the Atacama Desert in Chile, WISPIT 2b is also just the second young planet confirmed around a star that is essentially analogous to a young sun.

This makes the study of WISPIT 2b and its home protoplanetary disk, which is as wide as around 380 times the distance between Earth and the sun, the ideal laboratory to study interactions between planets and disks and the subsequent evolution of such systems.

"Discovering this planet was an amazing experience - we were incredibly lucky," team leader and Leiden University researcher Richelle van Capelleveen said in a statement. "WISPIT 2, a young version of our sun, is located in a little-studied group of young stars, and we did not expect to find such a spectacular system. This system will likely be a benchmark for years to come.”

The team captured an infrared image of the planet sitting in a gap in the disk as they conducted an investigation designed to discover if gas giants on wide orbits are more common around young or old stars. This was possible because the infant planet is still hot and glowing following its formation.

"We used these really short snapshot observations of many young stars - only a few minutes per object - to determine if we could see a little dot of light next to them that is caused by a planet," said Christian Ginski, lecturer at the School of Natural Sciences, University of Galway. "However, in the case of this star, we instead detected a completely unexpected and exceptionally beautiful multi-ringed dust disk.

“When we saw this multi-ringed disk for the first time, we knew we had to try and see if we could detect a planet within it, so we quickly asked for follow-up observations."

A separate crew of researchers from the University of Arizona imaged WISPIT 2b in optical light. These observations revealed that WISPIT 2b is still gathering matter.

"Capturing an image of these forming planets has proven extremely challenging, and it gives us a real chance to understand why the many thousands of older exoplanet systems out there look so diverse and so different from our own solar system," Ginski added. "I think many of our colleagues who study planet formation will take a close look at this system in the years to come."

Ginski added that the team was fortunate to have these incredible young researchers on the case of WISPIT 2b, adding that this will be the first of many breakthroughs to come from the next generation of astrophysicists.

"The planet is a remarkable discovery. I could hardly believe it was a real detection when Dr. Ginski first showed me the image," team member and University of Galway MSc student Jake Byrne said. "It's a big one - that's sure to spark discussion within the research community and advance our understanding of planet formation."

The team's research was published across two papers published on Tuesday (Aug. 26) in The Astrophysical Journal Letters.

The StarryStarryProcess builds upon the transit method that has been employed by NASA's TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler space telescope missions to detect exoplanets. It could be employed by astronomers to assess data from these missions and from NASA's forthcoming Pandora exoplanet-observing satellite.

"Many of the models researchers use to analyze data from exoplanets, or worlds beyond our solar system, assume that stars are uniformly bright disks," study team leader Sabina Sagynbayeva, of Stony Brook University in New York, said in a statement. "But we know just by looking at our own sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located and how bright or dark they are."

What do transits tell us?

TESS and Kepler have used the transit method to great effect to discover planets beyond the solar system. In fact, the majority of the over 5,000 worlds in the exoplanet catalog were discovered via the tiny dips in starlight they cause as they cross the face of their parent star.

Tracking how a star's light changes as a planet moves across its face from our position here on Earth helps build a light curve. Brightness falls slightly as the planet moves in front of the star, with minimum brightness achieved when the exoplanet is fully in front of the star. The brightness then steadily increases as the planet moves past the star, bringing the transit to a close.

In addition to helping discover planets, measuring transits can help determine the distance between a planet and its star, as well as the planet's size and rough surface temperature. Additionally, because chemicals absorb light at characteristic wavelengths, as starlight passes through the atmosphere of a planet, a process called spectroscopy can be used to determine the chemical composition of that atmosphere.

However, astronomers often find that light curves aren't as straightforward as they appear. In addition to the drops caused by planetary transits, scientists have spotted dips that are smaller and more complicated. The prevailing theory is that these are the result of "starspots" akin to the sunspots that punctuate the surface of our star, the sun.

The number of sunspots, which are cool and dark patches on the sun, varies across its 11-year solar cycle, with the maximum number of sunspots corresponding with maximum solar activity. They can often be used to predict solar activity and how the solar cycle is progressing.

Therefore, secondary dips in light curves can be used to determine how active the star is, which direction it is tilted, and the angle of the transiting planet's orbit. The StarryStarryProcess takes this to the next level, revealing even more about these characteristics.

"Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop," team member Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore, explained in the same statement.

"For example, at cool enough temperatures, stars can have water vapor in their atmospheres," Morris added. "If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we'd better be very sure that we’re not confusing the two."

To test the StarryStarryProcess, the team looked at the transits a planet called TOI 3884 b makes of its parent star, located around 141 light-years away. The planet is believed to be a gas giant, around five times the size of our planet but with 32 times its mass. TOI 3884 b was discovered in 2022 by TESS.

Using the StarryStarryProcess, the team determined that the parent star of TOI 3884 b has groups of starspots concentrated at its north pole, which is tilted toward Earth. This also means that TOI 3884 b crosses the poles of its parent star from our perspective as it makes its transits.

At the moment, the StarryStarryProcess can only be used in visible light, meaning it can't be applied to exoplanet observations made by the James Webb Space Telescope (JWST). However, the Pandora satellite, which is expected to launch later this year, will make its observations in multiple wavelengths of light, meaning that scientists can make use of this new model again once it starts collecting data.

"The TESS satellite has discovered thousands of planets since it launched in 2018. While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets," Allison Youngblood, TESS project scientist at NASA’s Goddard Space Flight Center in Maryland, said in the statement. "The more we understand the individual parts of a planetary system, the better we understand the whole — and our own."

The team's research was published on Monday (Aug. 25) in The Astrophysical Journal.

In this new model, superheavy dark matter particles could be trapped by exoplanets, losing energy and drifting toward that world's core. Once there, these superheavy dark matter particles accumulate until they collapse, forming a black hole. This black hole then ravenously eats its way out of its host planet.

This new dark matter/black hole theory doesn't work with all recipes of black holes, however. For instance, if dark matter particles meet and annihilate each other as some models suggest (as happens when electrons meet their antiparticles, positrons), then it wouldn't be possible for them to gather in quantities needed to collapse and birth a black hole.

Dark matter is troubling to scientists because, despite the fact that it accounts for 85% of the "stuff" in the universe, we have no idea what it is. The fact that dark matter doesn't interact with light means it can't be made up the electrons, protons, and neutrons that form the atoms that compose everything we see around us: the universe's ordinary matter — stars, planets, moons, living things, etc.. This lack of interaction with electromagnetic radiation also makes dark matter effectively invisible. This puzzle has led to scientists to suggest all types of different particles that might possibly account for dark matter, many of which have different properties.

But there's another caveat to the dark matter recipe needed for this process to occur. The constituent particles would have to have very large masses. This rules out one of the most highly favored dark matter candidate particles, the axion, a hypothetical particle with a very small mass.

"If the dark matter particles are heavy enough and don't annihilate, they may eventually collapse into a tiny black hole," University of California, Riverside researcher Mehrdad Phoroutan Mehr said in a statement. "If the dark matter particles are heavy enough and don’t annihilate, they may eventually collapse into a tiny black hole."

How are dark matter black holes born?

Currently, the lightest black holes we are aware of are so-called stellar mass black holes. These are thought to have masses between around 3 and 100 times the mass of the sun. The logic behind this is sound, as these black holes are born when massive stars run out of nuclear fuel at the end of their lives. As a supernova explosion ejects the outer layers of these stars, their stellar cores collapse.

That means the mass range of stellar mass black holes is set by the masses of the progenitor stars that created them. Furthermore, the lower mass is set by the fact that stars with less than 1.4 times the mass of the sun (a value known as the Chandrasekhar limit) can't go supernova, so can't birth a black hole or a neutron star. Instead, these stars leave behind a white dwarf.

There's another mass limit to consider, too. The Tolman–Oppenheimer–Volkoff (TOV) limit divides stellar cores that create black holes and those that birth neutron stars. Though less well defined than the Chandrasekhar limit, the TOV limit suggests that after ejecting most of its matter, a stellar core needs to have at least 2.2 to 2.9 times the mass of the sun to form a black hole.

This limit is uncertain, as currently the lightest black hole we have detected and confirmed is around 3.8 times the mass of the sun, while the heaviest neutron star ever detected weighs in at 2.4 solar masses.

These planet-eating black holes would be much more diminutive than even the lightest stellar mass black hole if they adopt the mass of the planet they devour. The team proposes that this process could occur within planets with masses the same as Jupiter, which has around 0.001 times the mass of the sun.

"In gaseous exoplanets of various sizes, temperatures, and densities, black holes could form on observable timescales, potentially even generating multiple black holes in a single exoplanet's lifetime," Phoroutan-Mehr said. "These results show how exoplanet surveys could be used to hunt for superheavy dark matter particles, especially in regions hypothesized to be rich in dark matter like our Milky Way's galactic center."

Of course, other than watching a planet devoured from the inside out, the creation pathway of stellar mass black holes and the TOV limit means that detecting a black hole with a mass less than the sun could support the team's theory.

"Discovering a black hole with the mass of a planet would be a major breakthrough," Phoroutan-Mehr said. "If astronomers were to discover a population of planet-sized black holes, it could offer strong evidence in favor of the superheavy non-annihilating dark matter model."

This new theory, combined with the growing catalog of exoplanets, with over 5,000 worlds beyond the solar system, means these planets can now be added to the celestial bodies that have been suggested as dark matter probes.

An example of that is the suggestion that certain dark matter candidates could become trapped in neutron stars, gathering and gradually annihilating each other thus heating these stellar remnants.

"So, if we were to observe an old and cold neutron star, it could rule out certain properties of dark matter, since dark matter is theoretically expected to heat them up," Phoroutan-Mehr said.

Dark matter trapping within exoplanets could also cause heating within these worlds or it could cause them to emit high-energy radiation.

"Today's instruments aren't sensitive enough to detect these signals. Future telescopes and space missions may be able to pick them up," Phoroutan-Mehr concluded. "As we continue to collect more data and examine individual planets in more detail, exoplanets may offer crucial insights into the nature of dark matter."

The team's research was published on Wednesday (Aug. 20) in the journal Physical Review D.

However, that still leaves four other planets in orbit around TRAPPIST-1 that could be habitable, with at least two or three of them in what is regarded as the "habitable zone" where temperatures would be suitable for liquid water to exist —- assuming an Earth-like atmosphere that can retain heat.

Previously, the James Webb Space Telescope (JWST) had failed to find evidence for an atmosphere around the two innermost planets in the TRAPPIST-1 system, world TRAPPIST-1b and TRAPPIST-1c. Now, we can add the next planet out, TRAPPIST-1d, to the list.

"Ultimately, we want to know if something like the environment we enjoy on Earth can exist elsewhere, and under what conditions," Caroline Piaulet-Ghorayeb of the University of Chicago and the Trottier Institute for Research on Exoplanets (IREx) at Université de Montréal, said in a statement. "At this point, we can rule out TRAPPIST-1d from a list of potential Earth twins or cousins."

All seven planets of the TRAPPIST-1 system are seen transiting, or passing in front of, their star. Although not even the JWST can see the silhouette of the transiting planet, it can detect where the star's light has been absorbed by molecules in the planet's atmosphere during the transit. This is called transmission spectroscopy.

Yet, despite using the JWST's sensitive Near-Infrared Spectrometer, or NIRSpec, astronomers led by Piaulet-Ghorayeb found no evidence for water, methane or carbon dioxide, all of which are common in Earth's atmosphere and which act as natural greenhouse gases to retain heat and keep a planet warm enough for liquid water.

"There are a few potential reasons why we don't detect an atmosphere around TRAPPIST-1d," said Piaulet-Ghorayeb. "It could have an extremely thin atmosphere that is difficult to detect, somewhat like Mars. Alternatively, it could have very thick, high-altitude clouds that are blocking our detection of specific atmospheric signatures — something more like Venus. Or, it could be barren rock, with no atmosphere at all."

The problem that the TRAPPIST-1 planets collectively face is their star. Red dwarfs, small and cool, seem at first glance to be unthreatening, but in reality they are tumultuous with frequent violent outbursts of radiation. These repeated flares can strip an atmosphere from a world a piece at a time. It is quite possible that this is the fate that has befallen TRAPPIST-1b, c and d. In particular, planet d seems like a real blow to our hopes of finding a world with an Earth-like atmosphere around TRAPPIST-1 because it resides on the inner edge of the system's habitable zone. That said, so does Venus in our solar system, and a Venus-like planet is still on the table. And there are four other planets still to go.

"All hope is not lost for atmospheres around the TRAPPIST-1 planets," said Piaulet-Ghorayeb. "While we didn't find a big, bold atmospheric signature for planet d, there is still potential for the outer planets to be holding onto a lot of water and other atmospheric components."

Planets e and f are definitely in the star's nominal habitable zone, g is at the outer edge like Mars is in our solar system, while planet h is beyond the habitable zone and will be almost certainly too cold to support an Earth-like atmosphere.

However, probing whether any of these outer planets has an atmosphere is more difficult. Their greater distance from their star means any spectral signature is weaker, perhaps too weak even for the JWST to detect.

But even if all the worlds around TRAPPIST-1, which is 40 light-years away, prove to be a bust, there are many more fish in the sea. Red dwarf stars are by far the most common type of star, making up about three-quarters of all stars in the Milky Way galaxy, and there are numerous other interesting planets around other red dwarfs, such as Teegarden's Star b, LHS 1140b and even Proxima Centauri b, even though the latter does not transit. And the search continues for rocky planets in the habitable zone of more sun-like stars — a search that the European Space Agency's PLATO mission, currently set to launch in December 2026, will accelerate.

The latest news regarding the search for an atmosphere around TRAPPIST-1d was published on Aug. 13 in The Astrophysical Journal.

Using JWST's Mid-Infrared Instrument (MIRI), the team imaged Alpha Centauri with a coronagraphic mask to remove the glare from the stars, allowing them to see much fainter objects like planets. That revealed a potential orbiting world some 10,000 times fainter than Alpha Centauri A.

While the planet candidate is in Alpha Centauri A's habitable zone — the range of distances from a star where it's possible for liquid water to exist on a world's surface — it is a gas giant and thus wouldn't be able to support life as we know it. Still, the potential planet is an exciting discovery.

For starters, it's sure to generate interest from sci-fi fans — after all, the "Avatar" film series' fictional moon Pandora circles a gas giant that orbits Alpha Centauri A.

But there's much intrigue within the realm of science, too. At a distance of just two astronomical units from its host star (twice the distance between Earth and the sun), the planet candidate, if confirmed, would be the closest to its host star ever imaged. It would also be the first planet imaged around a star that matches the sun in both age and temperature.

"With this system being so close to us, any exoplanets found would offer our best opportunity to collect data on planetary systems other than our own," Charles Beichman, the executive director of the NASA Exoplanet Science Institute at the California Institute of Technology (Caltech) and a senior scientist at NASA's Jet Propulsion Laboratory in Southern California, said in a statement.

The Alpha Centauri system hosts two confirmed exoplanets, both of them around the red dwarf star Proxima Centauri. There's still a long road ahead before the candidate Alpha Centauri A gas giant can join the list.

Subsequent JWST observations did not reveal additional evidence of the planet, though computer simulations suggest the planet might just have been too close to Alpha Centauri A to be imaged.

The team hopes that further observations by both JWST and the upcoming Nancy Grace Roman Space Telescope, scheduled to launch in May 2027, might provide the proof required to confirm the planet.

That would certainly give scientists much to study in the years to come. "[The planet's] very existence in a system of two closely separated stars would challenge our understanding of how planets form, survive, and evolve in chaotic environments," said Aniket Sanghi, a Caltech graduate student who co-led the research with Beichman.

The scientists report the new results in two papers that have been accepted for publication in The Astrophysical Journal Letters.

These fiery worlds share a similar density to Earth but orbit so close to their host stars that their scorching daytime temperatures melt the very rocks they're made of, creating possible oceans of magma that cover their surface.

While lava worlds represent an exciting new frontier in exoplanet science, much remains unknown about their dynamics, interiors and evolutionary paths. "Lava planets are in such extreme orbital configurations that our knowledge of rocky planets in the solar system does not directly apply, leaving scientists uncertain about what to expect when observing lava planets," Charles-Édouard Boukaré at York University in Toronto, co-author of a new study about lava worlds, said in a statement.

Given that lava planets have been identified as key targets for observation with NASA's James Webb Space Telescope (JWST), with five different programs already planned to study them, Boukaré and colleagues developed a conceptual framework — a "blueprint" of sorts — that outlines possible key characteristics, such as chemistry, surface conditions and other distinctive traits, to guide astronomers in identifying and analyzing these planets.

Using a numerical model, the researchers predicted the long-term evolution of lava planets over billions of years, from their formation to the point where they achieve a "thermal steady state." By combining insights from geophysical fluid mechanics, exoplanetary atmospheres, and mineralogy, the study reveals how the intense internal dynamics and shifting compositions of these exotic worlds likely unfolds over time.

But the model's foundation was based on findings made closer to home. "These processes, though greatly amplified in lava planets, are fundamentally the same as those that shape rocky planets in our own solar system," Boukaré said.

Interestingly, while lava planets are predicted to start out mostly molten right after they form, much like magma oceans on young planets in our solar system, they solidify nearly as quickly as their solar system counterparts despite being heated on their star-facing side. (Lava worlds are "tidally locked" to their host stars, with one hemisphere always in darkness and the other always in the very bright light.)

What makes lava planets unique is that, unlike rocky planets in our solar system, they maintain a shallow magma ocean on their sun-facing side for billions of years, even as their interiors slowly cool. Along the edges of this magma ocean, crystals continuously form from the molten rock, causing a constant separation of different chemical components between the solid crystals and the remaining liquid magma, according to the new study.

This ongoing process shapes and changes the planet over time, so the silicate atmosphere of an older lava planet reflects a chemically changed magma ocean — not the planet's original makeup. This means it's possible to tell the age of a lava planet by studying its atmosphere.

"Unlike the relatively low-density short-period exoplanet 55 Cancri e, bona fide lava planets are expected to have lost all their volatiles to space, but their 2,000–3,000 K[elvin; 1,727 to 2,727 degrees Celsius] daysides support an atmosphere of vaporized silicate rocks, which may be observable with the James Webb Space Telescope (JWST)," the researchers wrote in their paper, which was published in the journal Nature on July 29.

Additionally, young lava planets have relatively warm nightside temperatures around 1,500 K (1,227 degrees C), caused by heat from internal convection. As they age, without additional heat sources, their nightside cools significantly. A planet's current thermal state reflects its entire thermochemical history, making mantle temperature a key to understanding planetary evolution.

Measuring nightside temperatures is now possible with the JWST, providing insights into a planet's interior. Future telescopes like the Extremely Large Telescope, which is currently under construction in Chile, may also analyze silicate atmospheres, helping to reveal the complex interactions between a planet's atmosphere, molten surface and interior minerals.

What started as a "highly exploratory effort with few initial expectations" has grown into an exciting new frontier in exoplanet science, providing clear guidelines to help astronomers identify and study this new class of planets.

These predictions have played a key role in the team securing 100 hours of valuable observation time on JWST.

"We really hope we can observe and distinguish old lava planets from young lava planets. If we can do this, it would mark an important step toward moving beyond the traditional snapshot view of exoplanets," concluded Boukaré.

While signs of life on the world have failed to conclusively present themselves to the James Webb Space Telescope (JWST), the powerful space telescope has discovered that this planet is so rich in liquid water that it could be an ocean, or "Hycean" world.

"This has certainly increased the chances of habitability on K2-18 b" Nikku Madhusudhan, the University of Cambridge scientist behind the original K2-18b discovery as well as the new study, told Space.com. "This is a very important development and further increases the chance of a Hycean environment in K2-18 b. It confirms K2-18 b to be our best chance to study a potential habitable environment beyond the solar system at the present time."

The story regarding the habitability of K2-18 b began back in April 2025, when Madhusudhan and fellow researchers from the University of Cambridge announced they had found what they called the "strongest evidence yet" of life beyond the solar system around this distant super-Earth (it's around nine times as massive as our planet).

The evidence came from the tentative detection of molecules that, when found in the atmosphere of Earth, are typically the result of biological processes of living things. The pressure was then on to confirm these potential biosignatures: dimethyl sulfide and dimethyl disulfide.

The team set about this by observing four separate instances of K2-18 b crossing, or "transiting," the face of its parent red dwarf star, located about 124 light-years away, during its roughly 33-Earth-day orbit. Because chemicals absorb and emit light at characteristic wavelengths, when light from a parent star passes through a planet's atmosphere, the molecules in that atmosphere leave their telltale fingerprints in the spectrum of starlight.

"With four additional transit observations using JWST, we have measured the spectrum of K2-18 b’s atmosphere with unprecedented precision," Renyu Hu, the new study's team leader and a NASA Jet Propulsion Lab scientist, told Space.com. "The spectrum allowed us to conclusively detect both methane and carbon dioxide in the planet's atmosphere and to constrain their abundances. This information points to a planet with a water-rich interior."

Hu explained that the team searched for signals of dimethyl sulfide and other organic sulfur molecules in the spectrum using several independent models, but did not find conclusive evidence for their presence.

"This was not necessarily disappointing," Hu continued. "We're excited about establishing the planet’s water-rich nature."

Is K2-18 b a ocean world?

Saying it's now confirmed that K2-18 b is water-rich, Hu explained that the next step is to discover if the planet possesses a global liquid water ocean.

Ironically, one of the most positive signs of such an ocean is the fact that the atmosphere of this super-Earth appears to lack water vapor.

"The spectrum we obtained does not show signs of water vapor. If the atmosphere truly lacks water, this suggests that water has been depleted — most likely through condensation," Hu said. "On Earth, this process is known as the 'cold trap,' and geoscientists consider it essential for retaining water over billions of years by preventing it from escaping to space.

"Observing a similar process on an exoplanet would be very exciting. Rigorously confirming the absence of water can by itself be a scientifically important goal for future observations," Hu said.

However, Hu cautioned that the spectrum detected by the JWST could also be explained by an alternative model in which the atmosphere actually contains abundant water vapor.

Establishing whether K2-18 b and other similar temperate, sub-Neptune-sized planets possess liquid water oceans, Hu says, will also require detecting the presence of a broader set of atmospheric gases beyond methane and carbon dioxide. It would also require an absence of molecules like ammonia, carbon monoxide and sulfur dioxide, which, as of yet, have indeed not been detected in the atmosphere of K2-18 b

"This conclusion is based on theoretical work by my group and several others," Hu added. "With the new observations providing valuable context, we've summarized these insights into a roadmap to help guide future observations and studies."

Meanwhile, the search for the biosignatures, dimethyl sulfide and dimethyl disulfide, is far from done; while not hitting the significance level required for a confirmation, this research did provide a stronger signal from these molecules than were provided by previous examinations.

"The evidence for dimethyl sulfide in the present work is significantly higher than what we had with our previous observations in the same near-infrared wavelength range," Madhusudhan said. "However, this evidence is still not high enough to claim a conclusive detection.

"We also need to be able to distinguish dimethyl sulfide from other possible contributors, such as methyl mercaptan, which is also a biosignature on Earth."

It looks certain that K2-18 b will continue to hold the interest of astronomers for some time.

"It is great that we are able to infer tentative signs of potential biosignatures with current JWST observations, but significantly more time is needed for conclusive detections. A key question is whether the atmosphere contains one or more biosignatures," Madhusudhan said. "At the same time, extensive theoretical and experimental efforts are needed to robustly identify biological and non-biological pathways for candidate biosignature molecules."

One thing the team is sure of, though, is the progress made thus far in the study of K2-18 b wouldn't have been possible without the JWST. And, the $10 billion space telescope is set to play a key role in the future investigation of this super-Earth.

"Our observations and analyses add to the growing list of exciting discoveries that highlight the truly transformative science enabled by JWST," Hu concluded. "While we found its Near-Infrared Spectrograph [NIRSpec] particularly well suited to address the goals of our study, other JWST instruments or observational modes could provide complementary and highly valuable information to further enhance our understanding of this planet."

The team's research is available as a preprint on the paper repository arXiv.

These rogue planetary systems would also be much smaller than the solar system, possessing just a fraction of the total mass of our cosmic neighborhood.

The finding came about when a team of researchers used the James Webb Space Telescope (JWST) to examine young, isolated objects in space that are believed to have between five and 10 times the mass of Jupiter. These objects, unlike the planets of the solar system, were also unbound to a star and therefore free-floating in the universe.

These bodies could have formed in the same way stars form from collapsing clouds of gas and dust, hence their isolated nature. Yet, unlike stars, the free-floating planetary bodies would have failed to gather enough mass to trigger nuclear fusion in their cores, the process that defines what a main-sequence star is. That makes them akin to so-called "failed star" brown dwarfs, but with lower masses. Brown dwarfs have masses that range from 13 to 80 times the mass of Jupiter.

Alternatively, some free-floating planets are believed to have formed around stars from classic, swirling donuts of gas and dust called protoplanetary disks. They would've then been ejected from their home systems by gravitational interactions with their sibling planets and even with passing stars.

"These discoveries show that the building blocks for forming planets can be found even around objects that are barely larger than Jupiter and drifting alone in space," Belinda Damian, lead author of the research and a scientist at the University of St. Andrews, said in a statement. "This means that the formation of planetary systems is not exclusive to stars but might also work around lonely starless worlds."

The right stuff to spot planetary rogues

Believed to be the lowest mass bodies that can form from isolated clouds of gas and dust, free-floating planets are difficult to spot and study due to the fact that they emit very little light of their own. But the electromagnetic radiation free-floating planets do emit is mostly infrared light, the wavelength of light that the JWST is sensitive to.

As such, the study team honed in on eight young, free-floating planets with the powerful infrared space telescope.

The observations conducted between August and October of 2024 revealed detailed characteristics of the bodies, indicating that they have masses around that of Jupiter. Six of the free-floating planets exhibited an extended infrared emission generated by warm dust immediately around them. That indicated surrounding disks of gas and dust, the kind of structures that gather around infant stars to spawn planets.

Even more exciting than this was the detection of grains of silicates in these disks. That is an early indication of dust collecting together and crystallizing — and that, in turn, is the first stage in the formation of "rocky," or terrestrial, planets like Earth.

Traces of silicates have been seen around stars and even brown dwarfs before, but this is the first time these fingerprints have been found around much smaller free-floating planets. The team's finding backs prior research, which suggested that protoplanetary disks forming around free-floating planets could survive for several million years.

That is a period of time long enough to allow planets to form.

"Taken together, these studies show that objects with masses comparable to those of giant planets have the potential to form their own miniature planetary systems," team leader and University of St. Andrews astronomer Aleks Scholz said. "Those systems could be like the solar system, just scaled down by a factor of 100 or more in mass and size."

With the plausibility of these starless mini-planetary systems established and early fingerprints of their formation detected, the next step for astronomers will be to detect such a system.

"Whether or not such systems actually exist remains to be shown," Scholz said.

The team's research was published on Wednesday (July 30) in The Astronomical Journal.

Rogue, or "free-floating," planets are worlds that don't orbit a star. They earn their rogue status when they are ejected from their home systems due to interactions with their sibling planets or via gravitational upheaval caused by passing stars.

The most successful way of detecting an extrasolar planet, or exoplanet, in general is waiting until it crosses, or "transits," the face of its parent star. Being cosmic orphans without a stellar parent, however, rogue planets can't be detected in this way. Fortunately, a phenomenon first predicted by Einstein in 1915 offers a way to spot these rogue worlds.

"Free-floating planets, unlike most known exoplanets, don't orbit any star. They drift alone through the galaxy, in complete darkness, with no sun to illuminate them. That makes them impossible to detect using traditional planet-detection techniques, which rely on light from a host star," Przemek Mroz, study team member and a professor at the University of Warsaw, told Space.com. "To find these elusive objects, we use a technique called gravitational microlensing."

How Einstein became a rogue planet hunter

Einstein's 1915 theory of gravity, general relativity, suggests that objects with mass cause the very fabric of space to "warp." The bigger the mass, the greater the warp and thus the stronger the gravity that arises from the warp.

Gravitational lensing arises when light from a background source passes by the warp. Its path gets curved. This can amplify that background source, an effect that astronomers use with Hubble and the James Webb Space Telescope (JWST) to study extremely distant galaxies that would usually be too faint to see.

"This phenomenon occurs when a massive object, the lens, passes in front of a distant star (the source), magnifying the star's light due to the lens's gravity," Mroz explained. "The beauty of microlensing is that it works even if the lensing object emits no light at all.

"During microlensing events, the source star gets temporarily magnified. We can estimate the mass of the lensing object by measuring the duration and other properties of the event."

Mroz added that when microlensing events are generated by passing rogue planets, they are usually very short, lasting less than a day.

The particular microlensing event the team studied to reveal this new rogue world is designated OGLE-2023-BLG-0524 and was observed by Hubble on May 22, 2023, remaining buried in data from the space telescope.

"It was discovered in the direction of the Galactic bulge by the Optical Gravitational Lensing Experiment [OGLE] survey, and independently observed by the Korea Microlensing Telescope Network [KMTNet]," Mroz said. "The Einstein timescale of the event was just eight hours, making it one of the shortest microlensing events on record."

Based on the microlensing event’s properties, Mroz and colleagues were able to estimate that the lensing body object could be either a Neptune-mass planet located in the Milky Way's galactic disk, around 15,000 light-years away. Alternatively, the rogue world could be a larger but more distant Saturn-mass object in the Milky Way's galactic bulge, roughly 23,000 light-years away.

"Both scenarios are consistent with the microlensing signal we observed," Mroz said.

Hunting for planets in Hubble's archives

One of the most important tasks that faced the team upon the discovery of the microlensing event OGLE-2023-BLG-0524 was determining that this was indeed caused by a rogue planet, and not by a planet associated with a star but on a wide orbit far from its stellar parent.

They reasoned that if the planet had a nearby host star, within 10 times the distance between Earth and the sun (10 AU), they would have likely seen a second, longer-lasting microlensing signal from the star. The researchers saw no such signature, so they could rule out that the planet had a close stellar companion.

However, if the planet orbits a star at a much wider separation, greater than 10 AU, the odds of detecting the host star are much lower.

"This means we can’t fully rule out the wide-orbit scenario, but here's where it gets interesting," Mroz said. "Because the lens and the background star are slowly moving relative to each other, they will eventually separate in the sky.

"If we detect light from the lensing object at that point, we'll know it’s not completely free-floating."

Unfortunately, Mroz explained that the distance between the planet and the background star means their relative motion appears incredibly small, about 5 milliarcseconds per year.

"It will take at least a decade before we can hope to resolve them with current instruments, such as the Hubble Space Telescope or large ground-based telescopes," Mroz said.

Hubble was particularly useful in this rogue planet hunt because the region of the sky that hosts the microlensing event was observed by the long-serving space telescope way back in 1997. That's over 25 years before the microlensing event.

"That gave us a unique opportunity to test whether there might be a star associated with the lens," Mroz said. "According to our model, by 1997, the lens and source should have been separated by 0.13 arcseconds. That's tiny, but within Hubble's capabilities. If the lens were a bright star, we would have seen it in those old images. But we didn't."

The absence of detectable light at the expected lens position told the team that any potential host star would have to be very faint.

"Depending on the stellar population model we use, that rules out around 25% to 48% of possible companion stars," Mroz said. "That pushes us further toward the conclusion that this may truly be a free-floating planet."

Mroz explained that OGLE-2023-BLG-0524 was discovered by team member Mateusz Kapusta by chance while the team was following up on microlensing events.

"This discovery was partly serendipity!" Mroz said. "It was a lucky break, but we believe there are many more such opportunities hidden in the data.

"Microlensing events occur all the time in dense stellar fields, and many of those fields have been observed by Hubble in the past. That means there could be more interesting events waiting to be discovered in the Hubble data."

The team's research is available as a preprint on the paper repository arXiv.

Located about 35 light-years from Earth, L 98-59 is a cool, dim red dwarf star already known to host a compact system of small, rocky planets. The latest discovery, led by researchers at the Université de Montréal's Trottier Institute for Research on Exoplanets, confirms the presence of L 98-59 f, a super-Earth with a minimum mass 2.8 times that of our planet.

The newly discovered exoplanet follows an almost perfectly circular 23-Earth-day orbit around its star. The world receives roughly the same amount of stellar energy as Earth, placing it in the star's habitable zone — a range of distances where liquid water could exist under suitable atmospheric conditions, according to a statement from the university.

"Finding a temperate planet in such a compact system makes this discovery particularly exciting," Charles Cadieux, a postdoctoral researcher at the university and lead author of the study, said in the statement. "It highlights the remarkable diversity of exoplanetary systems and strengthens the case for studying potentially habitable worlds around low-mass stars."

L 98-59 f was discovered by reanalyzing data from the European Southern Observatory's (ESO) HARPS (High Accuracy Radial velocity Planet Searcher) and ESPRESSO (Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations) spectrographs. Since the exoplanet doesn't transit, or pass in front of, its host star from our perspective, astronomers spotted it by tracking subtle shifts in the star's motion that are caused by the planet's gravitational pull.

By combining the spectrograph data with observations from NASA's TESS (Transiting Exoplanet Survey Satellite) and James Webb Space Telescope (JWST) — and using advanced techniques to filter out stellar noise — researchers were able to determine the size, mass and key properties of all five planets.

The study shows that L 98-59 b, the innermost planet, is just 84% the size of Earth and half its mass, making it one of the smallest exoplanets measured. Tidal forces may drive volcanic activity on the system's two innermost planets, while the third's unusually low density suggests it could be a water-rich world unlike any in our solar system. This diversity offers a rare opportunity to investigate the formation and evolution of planetary systems beyond our own, team members said.

"These new results paint the most complete picture we've ever had of the fascinating L 98-59 system," Cadieux said. "It's a powerful demonstration of what we can achieve by combining data from space telescopes and high-precision instruments on Earth, and it gives us key targets for future atmospheric studies with the James Webb Space Telescope."

Because L 98-59 is small and nearby, its planets are especially well-suited for follow-up atmospheric studies. If L 98-59 f has an atmosphere, telescopes like JWST may be able to detect water vapor, carbon dioxide — or even biosignatures.

The new study was published July 12 in the journal Earth and Planetary Astrophysics.

Astronomers have seen what appears to be a forming planet carving out a complex pattern in a disk of gas and dust around a young star. The discovery of this spiral architect could help us better understand how planetary systems like the solar system came to be.

The infant extrasolar planet, or "exoplanet," is creating a spiral arm pattern in the planet-forming protoplanetary disk of the 10 million-year-old star HD 135344B, also known as SAO 206462, located in the Scorpius OB2-3 star-forming region. If 10 million years old doesn't seem particularly young, remember the sun is considered middle-aged — and its around 4.6 billion years old.

The discovery of the potential planetary culprit for this swirling spiral pattern was made using the Very Large Telescope (VLT) and its Enhanced Resolution Imager and Spectrograph ERIS) instrument. It may represent the first time astronomers have witnessed a planet actively forming within a protoplanetary disk.

"We will never witness the formation of Earth, but here, around a young star 440 light-years away, we may be watching a planet come into existence in real time," Francesco Maio, study team leader and a researcher at the University of Florence, said in a statement.

Maio and colleagues estimate this budding planet is around twice as large as Jupiter. It orbits HD 135344B at a similar distance to Neptune's orbit around the sun. That's about 30 times the distance between Earth and the sun.

And as this potential planet seems to carve channels into the protoplanetary disk of HD 135344B, it is gathering material to further facilitate its growth.

Baby exoplanet sweeps up stellar leftovers

Stars form from overly dense cool patches in vast clouds of interstellar gas and dust, which collapse under their own gravity. As these stars continue to grow, swirling clouds of gas and dust called protoplanetary disks settle around them. It is within this disk that planets will be born.

Astronomers predict that when this happens, these infant worlds sweep up material to build their own masses, creating intricate structures like rings and channels similar to the grooves in a record, and spirals resembling the spiral arms of the Milky Way. However, catching these exoplanet sculptors has been challenging.

Exemplifying this is the fact that astronomers had previously detected the spiral structure of HD 135344B's protoplanetary disk, using the VLT Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument — but had missed evidence of a planet causing it.

However, ERIS allowed the VLT and its operators to dive deeper into this protoplanetary disk, revealing a prime suspect for its shape: a hidden exoplanet sculptor.

This potential baby planet lurks at the base of one of the disk's spiral arms. That is exactly where scientists have predicted such a spiral-sculpting infant planet should dwell.

"What makes this detection potentially a turning point is that, unlike many previous observations, we are able to directly detect the signal of the protoplanet, which is still highly embedded in the disk,” Maio explained. "This gives us a much higher level of confidence in the planet’s existence, as we’re observing the planet's own light."

The team's research was published on Monday (July 21) in the journal Astronomy & Astrophysics.

Using NASA's Chandra X-ray spacecraft, astronomers have witnessed a distant, Jupiter-size world "shrinking" as its host star bombards it with heavy radiation.

The extrasolar planet, or "exoplanet," is named TOI 1227 b and is a cosmic baby at just 8 million years old (remember, Earth is around 4.5 billion years old). And, incredibly, the world orbits its star at a distance of just 8.2 million miles, a fraction of the distance between the sun and Mercury, with a year that lasts just 28 days. This proximity means the star, named TOI 1227 and located around 330 light-years away, is blasting the planet with powerful X-rays.

This radiation is stripping the exoplanet's atmosphere away; in fact, the atmosphere of TOI 1227 b is likely to be completely gone in around 1 billion years. This will reduce the exoplanet to nothing more than a small, rocky and barren core.

The team behind this research estimates TOI 1227 b will have ultimately lost the equivalent of two Earths' worth of mass by the conclusion of its transformation. As of now, the world has a mass around 17 times that of Earth's.

"It's almost unfathomable to imagine what is happening to this planet," Attila Varga, study team leader and a researcher at the Rochester Institute of Technology (RIT), said in a statement. "The planet's atmosphere simply cannot withstand the high X-ray dose it’s receiving from its star."

While this exoplanet's parent star is less massive than the sun (with about 10% the mass of our star) and is cooler and fainter in optical light, it is actually brighter than our star in X-rays.

"A crucial part of understanding planets outside our solar system is to account for high-energy radiation like X-rays that they're receiving," team member and RIT scientist Joel Kastner said in the statement. "We think this planet is puffed up, or inflated, in large part as a result of the ongoing assault of X-rays from the star."

The team used Chandra to determine just how much X-ray radiation is roasting TOI 1227 b. The researchers then used computer modeling to assess the impact of this radiation on the exoplanet and its atmosphere. This revealed that roughly every two centuries, the world loses the equivalent of Earth's entire atmosphere from its own atmosphere.

"The future for this baby planet doesn't look great," Alexander Binks, a study team member and researcher at Eberhard Karls University of Tübingen, said in the statement. "From here, TOI 1227 b may shrink to about a tenth of its current size and will lose more than 10 percent of its weight."

The researchers estimated the age of TOI 1227 b using estimates of its host star's velocity through space and comparing them with the speed of nearby stellar populations with known ages. The team also compared the surface brightness of TOI 1227 with models of stellar evolution.

TOI 1227 b stands out from other exoplanets aged less than 50 million years because, among the set, it seems to have the longest year and a host star with the lowest mass.

The team's research has been accepted for publication in The Astrophysical Journal and appears as a preprint on the repository site arXiv.

The extrasolar planet or "exoplanet" in question is TOI-2109b, which has five times the mass of Jupiter and is located around 870 light-years from our solar system. The planet orbits so close to its parent star, TOI-2109, that it has a year that lasts just 16 hours.

These characteristics mean that TOI-2109b is classified as an "ultrahot Jupiter," a rare class of planets that account for around 1 in 500 planets in the over 5,000 worlds in the catalog of known exoplanets. But TOI-2109b stands out even among those incredibly hot, star-hugging worlds.

"This is an ultra-hot Jupiter, and orbits much closer to its star than any other hot Jupiter ever discovered," Macquarie University Research Fellow Jaime A. Alvarado-Montes said in a statement."Just to put it into context, Mercury's mass is almost 6,000 times smaller than Jupiter's, but it still takes 88 days to orbit our sun.

"For a huge gas giant such as TOI-2109b to fully orbit in 16 hours, it tells us that this is a planet located super-close to its star."

That makes TOI-2109b the perfect laboratory to study planets' death spirals into their host stars, or more accurately, the phenomenon of orbital decay.

The three deaths of TOI-2109b

Alvarado-Montes and colleagues set about investigating TOI-2109b using archival data from multiple telescopes, including NASA's Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency (ESA) space mission Cheops.

This constituted data regarding the transits of TOI-2109b across the face of its parent star from 2010 to 2024.

"Using all of the data available for this planet, we were able to predict a small change in its orbit," Alvarado-Montes said. "Then we verified it with our theory and with our planet evolution models, and our predictions matched the observations. That's quite exciting."

The matching theoretical estimations and observational evidence suggested that the orbit of TOI-2109b will decay by around 10 seconds over the next three Earth-years. Though this is a tiny change, it proves TOI-2109b is spiraling toward its parent star.

The ultimate fate of TOI-2109b is uncertain, as there are three possible ways that this death spiral could play out.

The first and most dramatic final fate of TOI-2109b would see the ultrahot Jupiter plunge into its parent star. This will occur if the orbital decay of this planet begins to accelerate.

"The star will absorb it and kill it, of course, in the process – completely burn it, and the planet will disappear," Alvarado-Montes said.

This would create a flash of light that is similar to ZTF SLRN-2020, a signal first observed in May 2020 when a gas giant planet plunged into its red giant stellar parent.

The second possible fate of TOI-2109b is slightly less dramatic, but no less catastrophic.

This would happen if the orbital decay of the planet continues unabated and sees the gravity of its parent star generate destructive tidal forces within the planet. These forces would literally rip TOI-2109b apart.

"The gravitational interactions are so strong that the planet starts being distorted," Alvarado-Montes said. "It starts looking more like an elongated doughnut ... the gravity of the planet is no longer able to hold its spherical shape."

There is a third possible fate which would see the planet transformed rather than being destroyed.

In the third possible scenario for TOI-2109b, the intense radiation experienced by the ultrahot Jupiter strips away the planet's gassy outer layers in a process called photoevaporation. This would expose the rocky inner core of TOI-2109b.

"As the planet gets even closer to the star, all of the gas molecules could start being dissociated, and the planet gets smaller and smaller," Alvarado-Montes explained. "And if the planet shrinks quickly enough, then when the planet reaches the position where its Roche limit would have been, it's not going to be five Jupiter masses anymore, but it will be small enough that the Roche limit moves closer to the star, so it could escape destruction."

This could ultimately result in the creation of a rocky "super-Earth" around the size of Uranus or Neptune.

The team will continue to monitor TOI-2109b over the next three to five years, which should reveal the fate that will befall this doomed world.

The investigation of TOI-2109b has implications beyond its own fascinating and fateful situation. It provides astronomers the chance to study how hot Jupiters evolve and what happens when planets migrate toward their host stars.

"This planet and its interesting situation could help us figure out some mysterious astronomical phenomena that so far we really don't have much evidence to explain," Alvarado-Montes concludes. "It could tell us the story of many other solar systems."

The team's research was published on Tuesday (July 15) in The Astrophysical Journal.

That's the theory of a team of researchers who looked at hundreds of extrasolar planets, or exoplanets, observed by NASA's Transiting Exoplanet Survey Satellite (TESS).

TESS hunts exoplanets by catching them as they cross the face of, or "transit," their parent star, which causes a tiny drop in light from that star. The study team discovered that light from stars neighboring the one being transited could "contaminate" TESS' data, making it look like the transiting planet is blocking less light than it actually is. And that would make the planet look smaller than it is.

"We found that hundreds of exoplanets are larger than they appear, and that shifts our understanding of exoplanets on a large scale," University of California, Irvine researcher and team leader Te Han said in a statement. "This means we may have actually found fewer Earth-like planets so far than we thought."

Exoplanets throw shade

Exoplanets are so distant and faint that it is only on rare occasions that astronomers can image them directly.

That means the transit method has become the most successful way of detecting worlds beyond the solar system. It requires the planet and its star to be at the right angle in relation to Earth, and for astronomers to wait for the planet to make two transits to confirm its existence.

The transit method is best at spotting short-period planets orbiting close to their host stars, because they make more frequent transits. The method also favors larger planets, which block more light.

"We’re basically measuring the shadow of the planet," said team member and UC Irvine astronomer Paul Robertson.

The team gathered hundreds of TESS observations of exoplanets, sorting them by the width of the exoplanets in question.

They then used computer modeling and data from the European Space Agency's (ESA) star-tracking mission Gaia to estimate how much light contamination TESS is experiencing during its observations.

"TESS data are contaminated, which Te's custom model corrects better than anyone else in the field," said Robertson. "What we find in this study is that these planets may systematically be larger than we initially thought. It raises the question: Just how common are Earth-sized planets?"

Move over Earth-like worlds: ocean planets could be more common

Because of the biases of the transit method mentioned above, the number of exoplanets detected with TESS having sizes and compositions similar to those of Earth was already low.

"Of the single-planet systems discovered by TESS so far, only three were thought to be similar to Earth in their composition," Han explained. "With this new finding, all of them are actually bigger than we thought."

The likely outcome of this is that those exoplanets are larger ocean planets or "hycean worlds" covered by a large single ocean. Those worlds could also be gas giants smaller than Jupiter, like Neptune and Uranus.

That impacts the search for life because, though hycean worlds are packed with water, they could be lacking other ingredients needed for life to arise.

"This has important implications for our understanding of exoplanets, including, among other things, prioritization for follow-up observations with the James Webb Space Telescope, and the controversial existence of a galactic population of water worlds," Roberston added.

The next step for Han, Roberston, and colleagues is to re-examine planets previously deemed uninhabitable due to their size, to see if they are larger than previously thought.

In the meantime, the research is a reminder to astronomers to be cautious when assessing TESS data.

The team's research was published on Monday (July 14) in the Astrophysical Journal Letters.

Prior observations of the roughly 13 million-year-old star MP Mus (also known as PDS 66) located around 280 light-years away had failed to distinguish features in the swirling cloud of gas and dust, or protoplanetary disk, that surrounds it.

However, when astronomers reexamined the apparently featureless protoplanetary disk of this star using combined data from the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Space Agency (ESA) Gaia mission, they found it may not be quite so lonely after all.

The team detected a huge gas giant dwelling in the protoplanetary disk of MP Mus, which had been previously hidden. This represents the first time Gaia has spotted an extrasolar planet or "exoplanet" sitting in a protoplanetary disk, the disks of material around young stars that birth planets.

Such detections have typically been tough due to interference from the gas and dust of the protoplanetary disk. Until now, astronomers have only made three strong detections of planets within protoplanetary disks.

This new finding could help astronomers hunt more recently formed planets around infant stars.

Young exoplanets get into the groove

Planets form within protoplanetary disks through a process called core accretion, when larger and larger particles stick together via gravity, forming planetesimals, asteroids, and eventually planets.

As material from the protoplanetary disk is swallowed up by this process, the planets created begin to carve channels in the disk, akin to the grooves in a vinyl record.

When this team initially observed the protoplanetary disk around MP Mus in 2023 with ALMA, these were the kind of structures they had expected to see. Structures that were missing.

"We first observed this star at the time when we learned that most discs have rings and gaps, and I was hoping to find features around MP Mus that could hint at the presence of a planet or planets," team leader Álvaro Ribas from Cambridge's Institute of Astronomy said in a statement.

What the team found instead was a seemingly lonely star surrounded by a featureless disk of gas and dust that had none of the hallmarks of forming planets.

"Our earlier observations showed a boring, flat disc," Ribas said. "But this seemed odd to us, since the disc is between seven and ten million years old.

"In a disc of that age, we would expect to see some evidence of planet formation."

With their curiosity piqued, the team set about relooking at MP Mus again using ALMA, but in longer wavelengths of light. This allowed them to probe deeper into the disk, revealing a cavity in the disk close to the young star and two further "holes" further out, all of which were absent in the prior observations.

Further evidence of a planetary companion to MP Mus was about to be delivered.

More than just a first for Gaia

As Ribas and colleagues were examining MP Mus with ALMA, European Southern Observatory (ESO) researcher Miguel Vioque was looking at the young star using the now-retired star tracking spacecraft Gaia.

What Vioque discovered was that this young star is "wobbling." This is something that would usually be the effect of a planet in orbit gravitationally tugging on a star, but Vioque was aware that MP Mus' protoplanetary disk had, until that point, come up empty in terms of planets.

"My first reaction was that I must have made a mistake in my calculations, because MP Mus was known to have a featureless disc," Vioque explained. "I was revising my calculations when I saw Álvaro give a talk presenting preliminary results of a newly-discovered inner cavity in the disc, which meant the wobbling I was detecting was real and had a good chance of being caused by a forming planet."

The researchers came together, combining the Gaia and ALMA data with some computer modeling assistance to determine that the wobbling is likely caused by a gas giant with a mass between three and ten times that of Jupiter.

This giant planet appears to orbit MP Mus at a distance of between one and three times the distance between Earth and the sun.

"Our modelling work showed that if you put a giant planet inside the newfound cavity, you can also explain the Gaia signal," Ribas said. "And using the longer ALMA wavelengths allowed us to see structures we couldn’t see before."

As well as being the first time Gaia has spotted a planet within a protoplanetary disk, this is the first time an embedded exoplanet has been indirectly discovered by combining precise star movement data from Gaia with deep observations of the disk courtesy of ALMA.

"We think this might be one of the reasons why it's hard to detect young planets in protoplanetary discs, because in this case, we needed the ALMA and Gaia data together," said Ribas. "The longer ALMA wavelength is incredibly useful, but to observe at this wavelength requires more time on the telescope."

Ribas is hopeful that future ALMA upgrades, in addition to forthcoming telescopes, could be used to probe even deeper into protoplanetary disks.

This would not only reveal a hitherto undiscovered population of young embedded exoplanets, but it could help us understand how the solar system came to be around 4.5 billion years ago.

The team's research was published on Monday (July 14) in the journal Nature Astronomy.

The clingy, self-destructive extrasolar planet, or "exoplanet," in question is called HIP 67522 b. It orbits a young, 17 million-year-old star so closely that one of its years lasts just one Earth week.

Considering our middle-aged star, the sun, is 4.6 billion years old, the stellar parent of this clingy exoplanet (called HIP 67522) is a relative infant. This means it is bursting with energy.

Since the mid-1990s, when the first exoplanets were discovered, astronomers have pondered whether exoplanets can orbit their stars closely enough that stellar magnetic fields are impacted. Over 5,000 exoplanet discoveries later and astronomers still hadn't found the answer.

That is, until now.

"We hadn't seen any systems like HIP 67522 before; when the planet was found, it was the youngest planet known to be orbiting its host star in less than 10 days," team leader and Netherlands Institute for Radio Astronomy (ASTRON) researcher Ekaterina Ilin said in a statement. "I have a million questions because this is a completely new phenomenon, so the details are still not clear."

Kid planet triggers stellar parent

The team discovered HIP 67522 while using NASA's exoplanet hunting spacecraft TESS (Transiting Exoplanet Survey Satellite) to survey flaring stars.

TESS discovered some interesting characteristics of HIP 67522, prompting a follow-up investigation with the European Space Agency (ESA) mission Cheops (Characterizing Exoplanet Satellite).

"We quickly requested observing time with Cheops, which can target individual stars on demand, ultra precisely," Ilin said. "With Cheops, we saw more flares, taking the total count to 15, almost all coming in our direction as the planet transited in front of the star as seen from Earth."

Ilin and colleagues discovered that the stellar flares being thrown out by HIP 67522 occur when its clingy planet passes in front of, or "transits," the star. That means these flares are very likely triggered by the planet itself. The team theorizes this occurs because HIP 67522 b is so close to its star that it exerts a magnetic influence on the star.

As the planet whips around the star, it gathers energy, which is redirected as waves rippling down the star's magnetic field lines. When a wave hits the stellar surface, a massive flare is triggered.

"The planet seems to be triggering particularly energetic flares," Ilin explained. "The waves it sends along the star’s magnetic field lines kick off flares at specific moments. But the energy of the flares is much higher than the energy of the waves.

"We think that the waves are setting off explosions that are waiting to happen."

This is therefore the first hard evidence that planets can influence the behavior of their stars.

HIP 67522 b isn't just triggering flares facing nowhere, though. These induced flares are directed toward the world itself. In particular, it is bombarded with around six times the radiation a planet at this orbital distance usually would experience.

As you might imagine, this bombardment spells doom for HIP 67522 b. The planet is currently around the size of Jupiter, but it has around the density of candy floss.

The planet's wispy outer layers are being stripped away by harsh radiation, causing the planet to lose even the little mass it has. Over the next 100 million years, HIP 67522 b is expected to drop from the size of Jupiter to around the size of Neptune. The team doesn't actually quite know how extreme the damage these self-inflicted flares could be for HIP 67522 b.

"There are two things that I think are most important to do now. The first is to follow up in different wavelengths to find out what kind of energy is being released in these flares — for example, ultraviolet and X-rays are especially bad news for the exoplanet," Ilin said. "The second is to find and study other similar star-planet systems; by moving from a single case to a group of 10 to 100 systems, theoretical astronomers will have something to work with."

The team's research was published on Wednesday (July 2) in the journal Nature.

The extrasolar planet, or "exoplanet," designated TOI-4465 b is located around 400 light-years from Earth. It has a mass of around six times that of Jupiter, and it's around 1.25 times as wide as the solar system's largest planet. What is really exciting about TOI-4465 b, however, is the fact that it circles its star at a distance of around 0.4 times the distance between Earth and the sun in a flattened or "elliptical" orbit. One year for this planet takes around 102 Earth days to complete. Its distance from its star gives it an estimated temperature of between 200 and 400 degrees Fahrenheit (93 to 204 degrees Celsius).

This makes TOI-4465 b a rare case of a giant planet that is large, massive, dense, and relatively cool, existing in an underexplored region around its star in terms of what we know about planet size and mass.

Planets like TOI-4465 b are cool prospects for exoplanet scientists to study because they bridge the gap between "hot Jupiters," scorching planets that orbit so close to their stars that their years last a matter of hours, and frigid ice giant worlds like the solar system's own Neptune and Uranus.

Unfortunately, we don't know of many such worlds because they are difficult to detect.

"This discovery is important because long-period exoplanets, defined as having orbital periods longer than 100 days, are difficult to detect and confirm due to limited observational opportunities and resources," team leader and University of Mexico researcher Zahra Essack said in a statement. "As a result, they are underrepresented in our current catalog of exoplanets.

"Studying these long-period planets gives us insights into how planetary systems form and evolve under more moderate conditions.”

The rarity of such exoplanets makes TOI-4465 b a prime target for future investigation with the James Webb Space Telescope (JWST). But just how did the JWST's sibling, NASA spacecraft, TESS (Transiting Exoplanet Survey Satellite), detect such an elusive planet to begin with?

Don't cross TESS. Astronomers will hunt you down

TESS detects planets when they "transit" the face of their parent star, meaning they cross between their star and Earth. This causes a tiny dip in the light received from that star.

TOI-4465 b was spotted by TESS during a single fleeting transit event. That meant, in order to confirm this planet, the team needed to observe at least one more transit event. Something easier said than done due to some frustrating complications.

"The observational windows are extremely limited," Essack explained. "Each transit lasts about 12 hours, but it is incredibly rare to get 12 full hours of dark, clear skies in one location. The difficulty of observing the transit is compounded by weather, telescope availability, and the need for continuous coverage.”

To combat these issues, the team turned to the Unistellar Citizen Science Network, calling upon 24 of its citizen scientists across 10 countries. These amateur astronomers used their personal telescopes to observe TOI-4465 b's host star.

Combining this data with observations from several professional observatories resulted in the discovery of that elusive second transit, thus confirming TOI-4465 b.

"The discovery and confirmation of TOI-4465 b not only expands our knowledge of planets in the far reaches of other star systems but also shows how passionate astronomy enthusiasts can play a direct role in frontier scientific research," Essack said.

The discovery of this planet wouldn't have been possible without international collaborations and several initiatives, including the TESS Follow-up Observing Program Sub Group 1 (TFOP SG1), the Unistellar Citizen Science Network, and the TESS Single Transit Planet Candidate (TSTPC) Working Group.

"What makes this collaboration effective is the infrastructure behind it," Essack added. "It is a great example of the power of citizen science, teamwork, and the importance of global collaboration in astronomy."

The team's research was published on Wednesday (June 25) in The Astrophysical Journal.

The discovery came about when a team of scientists studied 78 planet-forming, flattened clouds of gas and dust, or "protoplanetary disks," in the Ophiuchus star-forming region. This stellar nursery, also known as the Rho Ophiuchi cloud complex, is located around 460 light-years from Earth, making it the closest star-forming region to our solar system.

The team discovered previously unseen rings, spirals and other substructures in the swirling, plate-like planet-forming clouds around a number of stars just a few hundred thousand years old. If that seems ancient, consider this: Our middle-aged star, the sun, is 4.6 billion years old.

The team's findings suggest stars and planets evolve together in environments that are rich in gas and dust.

Investigating the co-evolution of planets and stars

Stars are born when overly dense regions in vast clouds of gas and dust called molecular clouds collapse under their own gravity. This collapse creates a protostar wrapped in a pre-natal envelope of material from which it continues to gather mass.

This matter-harvesting continues until the star is sufficiently massive enough to trigger the fusion of hydrogen to helium at the heart of the star, the nuclear process that defines what a fully grown or main-sequence star is.

The end result is a young star surrounded by a flattened disk of gas and dust within which planets can begin to form. When planets begin to take shape in these disks, their gravitational influence can gather or eject materials. That process gives rise to substructures in the protoplanetary disk.

However, the big question is: At what point in the evolution of planetary systems do these substructures begin to appear?

That's a question astronomers have been attempting to answer using the Atacama Large Millimeter/submillimeter Array (ALMA), an array of 66 antennas in northern Chile that work together to act as form a single telescope.

In particular, two large programs conducted by ALMA, DSHARP and eDisk, have discovered intricate details of structures in protoplanetary disks.

DSHARP found that such structures are common in the disks that surround 20 young stars under 1 million years of age. Meanwhile, eDisk studied younger protostars that are just between 10,000 and 100,000 years old and thus still in their matter-harvesting stage. This revealed that structures present around 1 million-year-old stars are absent around stars 10 and 100 times younger.

That implies the characteristics of a protoplanetary disk are dependent on the age of its central star.

The new study's team looked at stars with ages between those studied in the DSHARP and eDisk programs, turning to super-resolution imaging provided by public software called "Python module for Radio Interferometry Imaging with Sparse Modeling," or (PRIISM), and applied this to ALMA archival data.

This allowed the researchers to obtain a resolution three times greater than what's provided by standard procedures for half of the imaged protoplanetary disks. The team's results were further bolstered by the fact their Ophiuchus sample was four times larger than what was used in the DSHARP and eDisk programs.

The investigation revealed 27 of the 78 examined disks had ring or spiral structures, 15 of which had never been seen before.

This revealed substructures form in disks that have widths 30 times the distance between Earth and the sun (30 astronomical units). This, in turn, implies that substructures form much earlier than previously thought — while such disks are still abundant with gas and dust.

In other words, infant stars and planets seem to evolve together — at least, in the Ophiuchus stellar nursery.

"These findings, bridging the gap between the eDisk and DSHARP projects, were enabled by the innovative imaging that allows for both achieving high resolution and a large number of samples," Ayumu Shoshi, team leader and a researcher at Kyushu University, said in a statement. "While these findings only pertain to the disks in Ophiuchus, future studies of other star-forming regions will reveal whether this tendency is universal."

The team's research was published in The Publications of the Astronomical Society of Japan

That's according to scientists who have found that lichen in the Mojave Desert managed to survive for 3 months under levels of intense radiation from the sun that had previously been considered lethal to this organism.

While the lichen was badly damaged, it was able to recover and eventually replicate. That indicates to scientists that other extraterrestrial life that requires photosynthesis could prosper on terrestrial or rocky extrasolar planets, or "exoplanets," even if they are exposed to radiation from their own star that had previously been considered deadly.

"The study was motivated by a curious observation," team member and Desert Research Institute scientist Henry Sun said in a statement. "I was just walking in the desert, and I noticed that the lichens growing there aren't green, they're black. They are photosynthetic and contain chlorophyll, so you would think they'd be green.

"So I wondered, 'What is the pigment they're wearing?' And that pigment turned out to be the world's best sunscreen."

Lichen is composed of algae or cyanobacteria that exist symbiotically with fungi. The lichen that formed the basis of this research is Clavascidium lacinulatum, or the "common lichen," found in arid regions across the globe, including Europe, Asia, North Africa, and, of course, the U.S.

Common lichen. Not so common sunscreen

Life on Earth thrives on light from the sun, which plants and other life forms use to create sugars via photosynthesis. But sunlight is a mix of electromagnetic radiation of different wavelengths, and some of this radiation is not so useful to life; in particular, ultraviolet light.

Terrestrial organisms have evolved to cope with Ultraviolet A (UVA) radiation and less common UVB radiation. In humans, UVA is associated with skin aging and wrinkle formation, while UVB causes skin damage like tanning, sunburn, and can even lead to skin cancer.

However, light that leaves our star also contains UVC radiation, which has a shorter wavelength than UVA or UVB light and carries more energy, making it much more harmful to life, damaging DNA, and preventing reproduction. In fact, UVC is so lethal that it can be used to sterilize air and water, wiping out microorganisms like bacteria and viruses.

Fortunately, our atmosphere filters out much of the ultraviolet light blasted at us from the sun, protecting life from its harshest effects. UVC radiation is completely absorbed, meaning it doesn't reach the surface of our planet. But terrestrial worlds in other star systems may not be so lucky.

This could be especially detrimental to life around so-called M-class and F-class stars, which are hotter and brighter than the sun and are known to belt out intense UVC radiation, especially during stellar flares.

"After the launch of the James Webb Space Telescope (JWST), which can see extremely far into space, the excitement shifted from finding life on Mars to these exoplanets," Sun said. "We're talking about planets that have liquid water and an atmosphere."

Sun and colleagues wanted to see how lichen coped with bombardment by UVC radiation, so they placed a sample next to a UVC lamp for 3 months in a controlled setting.

"In order for a microorganism to persist on a planet, it has to last longer than a day," Sun explained. "So, our experiment had to be long enough to be ecologically significant. We also wanted to go beyond just activity and demonstrate viability."

To their surprise, half the cells comprising the lichen regained the ability to replicate after water was reintroduced to them.

After further investigation with chemists from the University of Nevada, Sun and colleagues found that this is because the acids of the lichen are akin to nature's version of the additives used to make plastics UV-resistant.

Diving deeper, the team cut through the lichen, finding that the top layer was darker, almost like a suntan in humans. Furthermore, they found that when the fungi and the algae that make up lichen were separated, the algae died within minutes of UVC exposure.

The team surmised that because lichen isn't regularly exposed to UVC thanks to Earth's atmosphere, its protective layer evolved as a bonus of its UVA and UVB shielding rather than as an aid to survival.

"We came to the conclusion that the lichen's top layer—a less than millimeter thick skin, if you will—assures that all the cells below are protected from radiation," Sun continued. "This layer acts as a photostabilizer and even protects the cells from harmful chemical reactions caused by the radiation, including reactive oxygen."

As for this discovery's implications for life on other worlds, the team posits that some exoplanets may "be teeming with colonial microorganisms that, like the lichens in the Mojave Desert, are 'tanned' and virtually immune to UVC stress."

"This work reveals the extraordinary tenacity of life even under the harshest conditions, a reminder that life, once sparked, strives to endure," team leader and NASA Goddard Space Flight Center researcher Tejinder Singh said. "In exploring these limits, we inch closer to understanding where life might be possible beyond this planet we call home."

The team's research was published on June 12 in Astrobiology

The extrasolar planet, or "exoplanet," which has been designated TWA 7b, also happens to have the lowest mass of any planet that has been directly imaged beyond the solar system. With an estimated mass of around 100 times that of Earth or 0.3 times the mass of Jupiter, TWA 7b is ten times lighter than any exoplanet previously directly imaged.

TWA 7b was discovered in the debris rings that surround the low-mass star CE Antilae, also known as TWA 7, located around 111 light-years from Earth. CE Antilae is a very young star, estimated to be around just a few million years old. If that seems ancient, consider the sun, a "middle-aged" star, is around 4.6 billion years old.

CE Antilae, discovered in 1999, has long been a system of great interest to astronomers because it is seen "pole-on" from Earth. That means the disk of debris or "protoplanetary disk" that surrounds CE Antliae is seen 'from above' (or 'below'), revealing its full extent.

This has allowed astronomers to see structures in this disk that appear to have been created by the gravity of then-unseen planets and planetesimals, the "seeds" which gather mass to grow into full planets.

The disk of CE Antilae is divided into three distinct rings, one of which is narrow and bounded by two empty "lanes" mostly devoid of matter.

When imaging this ring, the JWST spotted an infrared-emitting source, which the team of astronomers determined is most likely a young exoplanet. They then used simulations that confirmed the formation of a thin ring and a "hole" exactly where this planet is positioned, corresponding to JWST observations.

The JWST is the ideal instrument to detect young low-mass planets like TWA 7b, which emit infrared radiation, the type of light the $10 billion space telescope is most sensitive to.

Directly imaging these planets is difficult because they are drowned out by light from their parent stars. The JWST is equipped with a coronagraph that blocks out the light from central stars, allowing the faint infrared emissions of orbiting exoplanets to be detected by its Mid-Infrared Instrument (MIRI).

That means, though this is the lowest mass planet ever imaged and the first exoplanet discovered by the JWST, it's a safe bet that the powerful space telescope will discover many more planets as it images even lighter worlds.

The team's research was published in the journal Nature.

Hot Jupiter extra-solar planets, or "exoplanets," are scorching hot gas giants around the size of Jupiter or above that orbit so closely to their parent stars that one of their years can last less than an Earth day. While hot Jupiters are rare, orbiting just 1% of stars, even more scarce are "double hot Jupiters." These exoplanet pairs are found in binary star systems with one planet orbiting around each of the twin stars.

That's a strange arrangement and one that scientists have been keen to decode as it seems to challenge theories of planet formation. This team of astronomers thinks they may have the key to this puzzle, finding that the normal, long-term evolution of binary systems can naturally lead to the formation of a hot Jupiter around each star.

The process investigated by the team is known as von Zeipel-Lidov-Kozai (ZLK) migration. This posits the idea that over periods of time, planets with unusual orbits or orbital angles can be influenced by the gravity of another object, leading them to become a hot Jupiter close to their parent star.

"The ZLK mechanism is a dance of sorts," team leader and Yale University astronomer Malena Rice said in a statement. "In a binary system, the extra star can shape and warp planets' orbits, causing the planets to migrate inward.

"We show how planets in binary systems can undergo a mirrored migration process, so that both stars end up with hot Jupiters."

To reach their conclusion, Rice and colleagues performed a number of simulations of the evolution of binary stars with two planets using the Grace computing cluster at the Yale Center for Research Computing with data from NASA's Exoplanet Archive and from the European Space Agency (ESA) star-tracking mission Gaia.

"With the right code and enough computing power, we can explore how planets evolve over billions of years — movements that no human could watch in a lifetime, but that still could leave imprints for us to observe," Yale researcher Yurou Liu said.

The unintended consequence of the team's research is that it makes planet-formation models a whole lot more interesting.

"We would expect giant planets to form far away from their host stars," Liu said. "This makes hot Jupiters both accessible and mysterious — and a worthwhile subject to study."

As for the hunt for more double hot Jupiters, the team suggests revisiting binary systems in which one hot Jupiter has already been discovered. The only catch is: these parent stars need to have a separation that is not too close and not too far, but just right.

"Our proposed mechanism works best when the stars are at a moderate separation," explained team member and Yale research Tiger Lu. "They need to be far enough apart that giant planets are still expected to form around each star, but close enough together for the two stars to influence each other during the system lifetime."

Goldilocks binary stars, anyone?

The team's research was published on June 10 in The Astrophysical Journal

The 8.4-meter telescope, equipped with the largest digital camera ever, will conduct the decade-long Legacy Survey of Space and Time (LSST), capturing the entire southern sky over Earth every 3 nights.

To get you properly prepped for the first images from Rubin, Space.com spoke to an array of scientists who will work with the observatory, as well as others who are just excited to see what images and data this groundbreaking instrument is set to reveal.

However, be warned: they're tight-lipped about just what images we will see.

"Until the images are revealed next week, all I can say is that people are going to be amazed at what we're able to see already," Andrés Alejandro Plazas Malagón, a researcher at Stanford University and part of the Rubin Observatory’s Community Science Team, told Space.com. "I am excited about using the largest digital camera in the world for astronomy — the LSSTCam, with 3.2 gigapixels — to survey the entire sky visible from its location in Chile over a 10-year period. This is something that has never been done before.

"We will be able to gather more data than any galaxy survey to date to help answer fundamental open questions in astronomy."

Mireia Montes: "It is going to be huge!"

Mireia Montes is a Ramón y Cajal Fellow at the Institute of Space Sciences (ICE-CSIC) who will use Rubin to track stars drifting between galaxies via the faint "intracluster light" they emit.

"Rubin is exciting because it is going to be huge! Surveys are normally limited by how much area they cover or how deep they go, following a method called the 'wedding cake strategy'," Montes said.

"This means they cover a large area but are not very detailed, or small areas in great detail. Large areas are good for having lots of galaxies, but depth is better for seeing faint things like the details of galaxies or very distant galaxies. You usually choose whether to go for depth or area. Rubin is going to provide both depth and area! This will help us to see things that are not usually very clear.

"The general public will see that the night sky is not as dark as we see it. In fact, when you look at deep images, you can see that there are objects (like stars and galaxies) everywhere you look. I think people are going to be amazed by the number of objects in this image, just as we were by the Hubble Deep Field ... but on a very different scale, as Rubin's camera is huge.

Rubin is going to show us the universe in a totally new way!"

Rubin and the dark universe

The wide-field view of Rubin will see the LSST gather data that could finally solve lingering mysteries surrounding dark energy, the force that accounts for around 68% of our universe's matter-energy content and causes the expansion of the cosmos to accelerate.

It is somewhat startling to consider that despite all of humanity's advances in science, we still only know what around 5% of the universe's contents are. All stars, planets, moons, animals, plants, and inanimate objects, everything we see is "baryonic matter" composed of atoms, but there is a lot more to the universe than this. The rest of the matter-energy content is known as the "dark universe."

Rubin has the right stuff to shine a light on the dark universe, which is divided into dark energy and dark matter, both of which account for about 17% of the universe's matter and energy but remains invisible because it doesn't interact with light.

"Studies of dark energy and dark matter are highly complementary with the Rubin Observatory and its LSST," Plazas Malagón said. "For dark energy, the LSST will measure the shapes and properties of billions of galaxies — an order of magnitude more than current photometric galaxy surveys — across cosmic time.

"This will allow Rubin to probe the growth of the large-scale structure of the universe, namely the cosmic web, which is dominated by dark matter, and the expansion history of the universe."

Plazas Malagón explained that the LSST will revolutionize the study of dark matter by mapping the sky with unprecedented depth and precision.

This will enable the detection of the smallest dark matter halos that surround small satellite dwarf galaxies and wrap around stellar streams. The observatory will also use a phenomenon first predicted in 1916 by Einstein called "gravitational lensing" to investigate the distribution of dark matter through large galaxies.

"It will test dark matter properties such as self-interactions, warm or ultra-light masses, and the presence of compact objects like primordial black holes," Plazas Malagón continued. "The LSST will also constrain exotic dark matter models — including axion-like particles — through stellar population measurements, and provide high-resolution maps of large-scale structure to explore how dark matter and dark energy interact.

"Combined with other experiments, LSST will offer powerful, complementary tests of dark matter's fundamental nature."

Among the most curious dark energy findings since its discovery in 1998 are hints from the Dark Energy Spectroscopic Instrument (DESI) that this mysterious force is weakening over time. The wide-field view of Rubin could help confirm this, which would prompt revisions to the standard model of cosmology, or Lambda Cold Dark Matter (LCDM), a model built on a constant dark energy strength.

"The LSST will collect vastly more data, which will help determine whether this is a real effect or just a fluctuation," Plazas Malagón explained. "In addition to studying dark energy, LSST will allow us to test the standard model of cosmology in other ways—examining the cold dark matter and dark energy hypotheses in the context of alternative models, including modified theories of gravity."

Luz Angela García Peñaloza: "An incredible milestone"

Luz Ángela García Peñaloza is a cosmologist in Bogotá, Colombia, specializing in dark energy. She explained why she is so excited about Rubin, its first images, and its ongoing mission.

"Rubin's first image release is an incredible milestone for the astronomical community. This observatory will cover the largest patch of the sky ever, capturing the light of approximately 20 billion galaxies.

Rubin (or LSST) is not only an impressive telescope that will complement the cosmic cartography we are doing with other galaxy surveys, but also a fantastic piece of engineering that will be online for the next 10 years.

We don't know yet what kind of images they will release on Monday, but I'm looking forward to seeing a deep field with tens of thousands of galaxies and stars. Remarkably, Vera Rubin is going to observe many, many galaxies in one night; thus, I expect to see beautiful images of the sky.

Rubin will help us constrain the Large Scale Structure of the universe and, along the same lines, the nature and dynamics of dark energy."

Rubin tracks stellar exiles, failed stars, supernovas and more

While Rubin will excel at studying galaxies en masse, some scientists will be interested in using its detailed view to look at what lies between those galaxies, namely, faint intracuster light.

"These processes are linked to the formation of clusters of galaxies, which are the largest structures bound by gravity in the universe," Mireia Montes is a Ramón y Cajal Fellow at the Institute of Space Sciences (ICE-CSIC), told Space.com. "Our understanding of the processes that form intracluster light is limited by small datasets. With Rubin, however, we will finally have the depth and numbers required to understand this light much better."

Montes added that the filters employed by Rubin will enable astronomers to determine the type of stars between galaxies that give rise to intracluster light.

That should then lead to the revelation of the origins of these "orphan" stars and how they came to drift between galaxies.

Rubin may also excel in spotting another type of faint stellar outcast, so-called "failed stars" or brown dwarfs. These are bodies that form like stars from a collapsing cloud of gas and dust, but fail to gather enough mass to trigger the nuclear fusion of hydrogen to helium in their cores, the process that defines what a main sequence star is.

The infrared vision of Rubin's Simonyi Survey Telescope combined with its wide field of view and ability to see deep into space, will make it the perfect instrument for discovering faint, infrared-emitting objects like brown dwarfs.

In fact, researchers have predicted that Rubin could detect thousands of brown dwarfs in the Milky Way, increasing our catalog of these "failed stars" by 20 times.

That could help us better understand the mass limit at which a star "succeeds" and becomes a star rather than a brown dwarf, and thus how our galaxy took shape.

Giuseppe Donatiello: "We must have an open mind to anything!"

Giuseppe Donatiello is an amateur astronomer from Italy who, thus far, has discovered a staggering 11 new dwarf galaxies in the local neighborhood of the Milky Way.

"Thanks to deep surveys, important discoveries have come in the Local Group, in particular, bizarre and decidedly unconventional objects have emerged. Rubin will certainly bring other similar discoveries, pushing their detection further," Donatiello said.

"The ability to go very deep will allow us to better define the timing in cosmic evolution, from the first stars to the current galaxies. Having such an instrument at our disposal does not limit the possibilities of observation, and we must have an open mind to anything new.

"Nature is more imaginative than we are!"

The future of astronomy is bright

This cursory list above is far from the extent of the phenomena that will be investigated by Rubin as it conducts the LSST.

"There will be major improvements in almost every area of astronomy," Montes said. "Understanding better our own Milky Way, the evolution of galaxies, finding more low-mass galaxies that will allow us to understand better how galaxy formation occurs at those masses, mapping the mass of our universe, and therefore understanding better our universe."

Plazas Malagón added that some of the other key questions the groundbreaking observatory could answer include: Are there undiscovered planets in the outer solar system (e.g., Planet Nine or Planet X)? What explosive and transient events occur in the universe? How do stars evolve and die? What are the electromagnetic counterparts to gravitational wave and neutrino events? What is the structure of the Milky Way's halo, disk, and bulge? What is the local galactic neighborhood like? Are there hazardous asteroids or comets that could impact Earth?

Phew! Little wonder scientists (and Space.com) are excited!

"I'm thrilled to see what the scientific community will do with this data," Alejandro Plazas concluded. "I'm especially excited about the new questions that will emerge — questions we haven't even imagined yet. We've built a discovery machine, and that's incredibly exciting to me.

"One of the most exciting aspects is the unexpected discoveries that lie ahead!"

The observations expand the range of environments where habitable worlds might form, the researchers say. Previously, astronomers thought these harsh conditions might not be conducive to the formation of planets. Ultraviolet (UV) radiation "was long thought to pose a serious threat to the formation of planets around nearby, smaller stars," Konstantin Getman, a research professor in the Department of Astronomy and Astrophysics at Penn State and co-author of a new paper describing the findings, told Space.com.

However, the results, published May 20 in The Astrophysical Journal, show that even under these harsh ultraviolet conditions, protoplanetary disks — swirling rings of gas and dust where planets are born — can still survive and evolve.

"We cannot go back in time to study how the exoplanets we observe [today were] formed," study co-author María Claudia Ramírez-Tannus, an astronomer at the Max Planck Institute for Astronomy in Heidelberg, Germany, told Space.com. "Instead, we need to look for their younger counterparts, which are planet-forming disks that exist in extreme environments with intense ultraviolet radiation."

The study was intended as a follow-up to 2023 research that suggested Earth-like planets can indeed form in such harsh environments.In the new study, the international team focused on XUE 1, the disk surrounding a young star in this extreme environment, to investigate the disk's size, mass, temperature and chemical composition.

XUE 1 is bathed in ultraviolet radiation that's far more intense than anything our own solar system has ever experienced. "In fact, if XUE 1 was placed at the location of our solar system's sun, it would receive 100,000 times less UV energy every second than it does right now," Bayron Portilla Revelo, a postdoctoral scholar in the Department of Astronomy and Astrophysics at Penn State and lead author of the new study, told Space.com.

"A very different idea"

JWST was key to the new discovery. The telescope has revolutionized the study of irradiated protoplanetary disks, offering the sensitivity and resolution needed to observe them from thousands of light-years away. "JWST is the only instrument with the sensitivity to observe relatively faint disks in very distant regions," Ramírez-Tannus said.

The team took advantage of JWST's Mid-Infrared Instrument (MIRI), which captures the cosmos in mid-infrared wavelengths of light. They used observations collected in 2023, supplemented by additional observations from the Visible and Infrared Survey Telescope for Astronomy, the Hubble Space Telescope, and the Spitzer Space Telescope.

That data allowed the team to observe the emission from a disk that is 5,500 light-years away. To interpret the observations, the team introduced the first thermochemical computational model driven by JWST/MIRI and archival data to simulate how light, heat and chemical reactions interact within the XUE 1 protoplanetary disk.

Thermochemical models offer a big advantage for studying planet-forming disks because they let astronomers explore details such as how much material is available to form planets. "This is crucial for understanding how planetary systems like our own come to be," Portilla Revelo said.

On the other hand, thermochemical models are computationally demanding and require a large amount of data to be effective. XUE 1 has been poorly observed so far, so the limited data made the protoplanetary disk difficult to model.

The model produced synthetic light spectra, which were then compared to the real data. By matching the simulations with observations, the researchers inferred critical properties of the disk, including its temperature, density and chemical makeup.

Their analysis revealed a compact, truncated disk, where intense ultraviolet radiation significantly alters both gas temperatures and the chemistry taking place. Among the most striking findings was the presence of water — one of the key ingredients for Earth-like planets — even in such a hostile environment.

Crucially, the modeling also showed that the inner region of the disk — the zone where rocky, potentially habitable planets can form — appears to be shielded from the worst ultraviolet radiation.

"Our model indicates that the innermost part of the disk, where planets like Earth can form, seems to be unaffected by the damaging external UV radiation," Portilla Revelo said.

"Before the observations were taken, scientists had a very different idea of what the spectrum would look like," he added. "Our modeling helps explain why the JWST spectrum appears the way it does. While UV light from nearby stars strongly affects the outer regions of the disk — where giant planets are likely to form — it has little direct impact on the inner regions, which are the source of the light detected by JWST."

The findings suggest that planet formation may be more resilient than previously thought, thus expanding the range of environments where life-supporting worlds might emerge and offering a rare glimpse into the diverse stellar nurseries of our galaxy.

"By studying more of these regions — especially those exposed to strong UV light from nearby massive stars — we can better understand how such intense environments affect disks around stars of all masses and sizes," Getman said.

The exoplanet — named 14 Herculis c, or 14 Her c for short — orbits a sunlike star about 60 light-years from Earth in the constellation Hercules. In the new JWST image, it appears as a faint, fuzzy orange dot, its color a result of heat radiating from its atmosphere translated into visible hues.

Astronomers estimate that 14 Her c formed around 4 billion years ago and has a frigid atmospheric temperature of just 26 degrees Fahrenheit (minus 3 degrees Celsius).

14 Her c orbits its star at a distance of about 1.4 billion miles (2.2 billion kilometers), or roughly 15 times farther from its star than Earth is from the sun. If placed in our solar system, it would sit between Saturn and Uranus.

But, unlike the flat, well-ordered orbits of planets in our solar system, the 14 Herculis system is dramatically misaligned. Its two known planets, including 14 Her c, orbit at angles of about 40 degrees to each other, creating an "X"-like crossing pattern around their star.

This unusual layout may have been caused by the early ejection of a third massive planet from the system, throwing the remaining two into a gravitationally turbulent "planetary tug of war," Balmer said.

"These wobbles appear to be stable over long time scales," he said. "We're trying to understand what kinds of planet-planet scatterings could produce such an exotic configuration of orbits."

This instability turned out to be a scientific advantage for Balmer's team. Of the nearly 6,000 known exoplanets, only a small fraction have been directly imaged.

"Doing this is very technically challenging," said Balmer. Planets shine thousands — and, in some cases, even millions or billions — of times fainter than the stars they orbit, so they "are like fireflies next to lighthouses," he said.

Most directly imaged exoplanets are hot, young gas giants that emit enough infrared light to stand out from the intense glare of their host stars. In contrast, colder and older planets like 14 Her c are usually far too dim to detect.

The planet's tilted, off-kilter orbit, however, "is great news for direct imaging," Balmer said. "We could confidently predict that JWST could resolve the outermost planet in the system."

Using the telescope's specialized starlight-blocking device known as a coronagraph, Balmer and his team succeeded in isolating the planet's faint infrared glow.

"We are now able to add to the catalog older exoplanets that are far colder than we've directly seen before Webb," Balmer said in a statement.

Based on 14 Her c's estimated age of around 4 billion years, its mass of about seven times that of Jupiter, and computer models of how planets evolve, the researchers expected the planet to appear brighter — or emit more heat — than it actually does in the JWST image.

"The planet's actually significantly fainter than what we'd expect," said Balmer. "We don't think that this is a problem with the evolutionary models, however."

Probing the world's atmosphere, JWST detected carbon dioxide and carbon monoxide at temperatures where methane would typically be expected, which suggests that strong updrafts carry hot gases from deep within the atmosphere to colder upper layers, Balmer said. These gases, possibly along with thin icy clouds, reduce the heat escaping into space, making the planet appear cooler and fainter than expected.

With 14 Her c, astronomers have broadened the range of exoplanets they can study. By examining planets with diverse masses, temperatures and orbital histories, scientists hope to gain a deeper understanding of how planetary systems, including our own, form and evolve.

"We want to understand how these planets change, because we want to understand how we got here," said Balmer.

The proposed small probe, known as the Gravity Imaging Radio Observer (GIRO), would use gravity fields to precisely map the interiors and compositions of the outer planets and other celestial bodies.

"GIRO is a small radio probe that reflects radio signals sent from the host spacecraft that carried and released it," Ryan Park, principal engineer at NASA and supervisor of the Solar System Dynamics group at the Jet Propulsion Laboratory, told Space.com in an email.

Park and his colleagues have designed GIRO to measure subtle variations in the gravitational fields of planets, moons and asteroids. They described the concept for the new probe in a paper published May 29 in The Planetary Science Journal.

"As the probe and the host spacecraft orbit (or fly by) a target body together in formation, variations, or 'lumpiness,' in the body's gravity field cause very small changes in the orbits of both the probe and the host spacecraft," Park said. "These changes can be measured using the Doppler effect in the radio signals."

By analyzing these Doppler signatures and mapping these gravity fields with high precision, researchers can infer the internal structure and dynamics of planets, moons and other celestial bodies. This insight helps answer fundamental questions about their mass, density, composition, formation history, and potential for geologic or volcanic activity — making GIRO a powerful, high-precision tool for future space exploration missions.

"GIRO would be particularly useful — and even essential — for problems that require the recovery of high-accuracy gravity fields, exploration of risky environments, and/or situations with limited data acquisition opportunities," Park said.

High-accuracy gravity data is crucial in situations where the gravitational signal is faint, such as determining the mass of a small asteroid or detecting changes in the gravity field of a planetary moon over time.

"Risky environments refer to places where it is practically challenging to conduct flybys or orbits," Park explained. A good example is the complex and potentially dangerous environment posed by the rings of Uranus. "Limited data acquisition applies to cases where only a handful of flybys or a short period of orbiting are feasible," he added.

The battery-powered, spin-stabilized probe's high accuracy, low cost and ability to carry multiple probes at once could help solve these challenging problems.

"Compared to conventional ground-based radiometric tracking, GIRO is expected to provide accuracy that is 10 to 100 times better," Park said. "This level of precision is important for planetary science because it allows for much more detailed mapping of gravity fields, revealing subtle features of a planet or moon's interior structure."

By matching the basic capabilities of past missions like GRAIL, GIRO can cut costs and complexity by using lightweight, low-power radio components while delivering accurate gravity measurements, according to Park.

This means "gravity science can be conducted as part of broader exploration missions rather than requiring dedicated spacecraft," he explained.

In addition, GIRO may open the door to exploring smaller celestial bodies and remote planetary systems that might advance our understanding of how planets form and evolve and whether they might harbor the conditions for life.

Designing a GIRO gravity experiment comes with its own set of challenges, most of which revolve around how the mission is planned. To get accurate data, the probes must be released into carefully chosen orbits that not only allow for precise gravity measurements but also maintain a strong radio connection with the main spacecraft.

For outer-planet missions, GIRO probes will be battery-powered, so all measurements must be completed before the batteries are depleted after 10 days. However, for missions closer to the sun, there is an option to recharge batteries using sunlight.

On top of that, the probe's orbits must comply with strict planetary protection rules, including how long they stay in orbit and how they are safely disposed of afterward to avoid contaminating other worlds.

According to Park, GIRO could technically be integrated into a planetary mission within one to three years. Though budgetary and political constraints would influence this timeline.

"The most important milestones before integration involve building and testing flight-like prototypes in environments that closely simulate actual mission conditions," Park said. "Once these milestones are met and a mission opportunity is identified, GIRO could be incorporated into the payload for upcoming missions, such as those targeting asteroids, moons or outer planets."

Using the James Webb Space Telescope (JWST), astronomers have discovered a planetary system orbiting a youthful star located 300 light-years away. The system's two planets, YSES-1 b and YSES-1 c, are packed with coarse, rough, and frankly irritating silica material (we get you, Anakin, it does get everywhere).

Astronomers say this discovery around a star that is just 16.7 million years old could hint at how the planets and moons of our 4.6 billion-year-old solar system took shape. As both planets are gas giants, they could offer astronomers an opportunity to study the real-time evolution of planets like Jupiter and Saturn.

"Observing silicate clouds, which are essentially sand clouds, in the atmospheres of extrasolar planets is important because it helps us better understand how atmospheric processes work and how planets form, a topic that is still under discussion since there is no agreement on the different models," team member Valentina D'Orazi of the National Institute for Astrophysics (INAF) said in a statement. "The discovery of these sand clouds, which remain aloft thanks to a cycle of sublimation and condensation similar to that of water on Earth, reveals complex mechanisms of transport and formation in the atmosphere.

"This allows us to improve our models of climate and chemical processes in environments very different from those of the solar system, thus expanding our knowledge of these systems."

Building a 'sandcastle' world

One of these extrasolar planets, or "exoplanets," YSES-1 c, has a mass around 14 times the mass of Jupiter. On YSES-1 c, this silica matter is located in clouds in its atmosphere, which gives it a reddish hue and creates sandy rains that fall inward towards its core.

We guess that the future Darth Vader didn't build too many sandcastles in his youth, but that process is analogous to the formation of sandy matter that YSES-1 b is undergoing.

Already possessing a mass around six times that of Jupiter, the still-forming sandcastle planet YSES-1 b is surrounded by a flattened cloud or "circumplanetary disk" that is supplying it with building materials, including silicates.

Not only is this the first direct observation of silica clouds (specifically iron-rich pyroxene or a combination of bridgmanite and forsterite) high in the atmosphere of an exoplanet, but it is also the first time silicates have been detected in a circumplanetary disk.

The JWST was able to make such detailed direct observations of both planets thanks to the great distances at which they orbit their parent star, which is equivalent to between 5 and 10 times the distance between the sun and its most distant planet, the ice giant Neptune.

Though this technique is still restricted to a small number of planets beyond the solar system, this research exemplifies the capability of the JWST to provide high-quality spectral data for exoplanets. This opens the possibility of studying both the atmospheres and circumplanetary environments of exoplanets in far greater detail.

"By studying these planets, we can better understand how planets form in general, a bit like peering into the past of our solar system," added D'Orazi. "The results support the idea that cloud compositions in young exoplanets and circumplanetary disks play a crucial role in determining atmospheric chemical composition.

"Furthermore, this study highlights the need for detailed atmospheric models to interpret the high-quality observational data obtained with telescopes such as JWST."

The team's results were published on Tuesday (June 10) in the journal Nature, the same day as they were presented at the 246th meeting of the American Astronomical Society in Anchorage, Alaska.

The discovery of the exoplanet, a super-Earth called Kepler-735c, is all down to something called transit timing variations, or TTVs for short.

Let's set the scene. One of the primary ways of discovering exoplanets is by looking for when they transit, or pass in front of, their star. As they do so, they block a small fraction of that star's light, and, based on the size of this dip in stellar brightness, we can determine how large the transiting planet must be. Indeed, this was how the most successful exoplanet hunter so far, NASA's Kepler space telescope, discovered over 3,300 confirmed exoplanets and thousands more candidates.

There are downsides to detecting exoplanets via transits, however. One is that the technique is biased toward planets on short orbits close to their star, which means they transit more often and are easier to see. Transits also require a precise alignment between the orbital plane of a planetary system and our line of sight. Even a small tilt might mean we cannot see planets on wider orbits transiting.

Those unseen planets on wider orbits can still make their presence felt, however, in the form of TTVs. Ordinarily, transits are as regular as clockwork, but in some cases astronomers have noticed that a planet's transit can be delayed, or occur ahead of schedule, and that this is being caused by the gravity of other planets tugging on the transiting world.

Sometimes we can see those other planets transiting as well — the seven-planet TRAPPIST-1 system is a great example. Often, though, we can't see the planet that is causing the variations, but the size and frequency of the TTVs can tell us about the orbital period and mass of these hidden worlds.

One such planet that has been found to experience TTVs is Kepler-725b. It's a gas giant planet orbiting a yellow sun-like star that was discovered by the now-defunct Kepler spacecraft.

"By analyzing the TTV signals of Kepler-725b, a gas giant planet with a 39.64-day period in the same system, the team has successfully inferred the mass and orbital parameters of the hidden planet Kepler-725c," Sun Leilei, of the Yunnan Observatories of the Chinese Academy of Sciences, said in a statement. Sun is the lead author of a new study revealing the existence of this hidden world.

Kepler-725c's mass is quite significant — 10 times greater than the mass of Earth. This places it in the upper echelons of a type of planet called super-Earths — giant, probably rocky worlds. We don't have an example of a super-Earth in our solar system, so we don't really know what such planets are like. Planetary scientists are still grappling with theoretical models that attempt to describe the properties of super-Earth worlds. Would they be wrapped in a dense atmosphere? Could they maintain plate tectonics? How would their higher surface gravity affect the evolution of life? Definitive answers to these questions have not yet been forthcoming.

Meanwhile, the planet's orbit is unusual to say the least. It is highly elliptical, with an eccentricity of 0.44. For comparison, Earth's orbit has an eccentricity of 0.0167 and is therefore close to circular; at the other extreme, an orbital eccentricity of 1 would be parabolic. Kepler-7825c's orbit is oval-shaped, meaning that at some points in its orbit it is much closer to its star than at other times. While overall Kepler-725c receives 1.4 times as much heat from its star as Earth does from the sun, this is just the average over the course of its orbit, and at times it is receiving less.

If Kepler-725c has an atmosphere, then the difference in solar heating at different times in its orbit could wreak havoc on its climate. In fact, the high orbital eccentricity actually means that the exoplanet only spends part of its orbit in the habitable zone, which is a circular zone around the star at a distance where temperatures are suitable for liquid water on a planet's surface.

Does this mean that Kepler-725c is only habitable for part of its 207.5-Earth-day year? What would happen to any life that might exist on the planet during the periods that it is outside of the habitable zone? Again, these are theoretical problems that scientists have been wrestling with, but now the existence of Kepler-725c suddenly makes them very real problems. However, because we do not see Kepler-725c transit, it will not be possible to probe its atmosphere with the James Webb Space Telescope, which uses sunlight filtered through a planet's atmosphere to make deductions about the properties and composition of that atmosphere.

Fortunately, there may be more such worlds out there to study. It is expected that when the European Space Agency's PLATO (PLAnetary Transits and Oscillations of stars) spacecraft launches in 2026 as our most sensitive exoplanet-detecting mission yet, it will be able to find many more worlds through TTVs. And, unlike radial velocity and transit measurements, which tend to be biased toward finding short-period exoplanets, TTVs open a window onto planets on wider orbits that are not seen to transit.

"[Kepler-725c's discovery] demonstrates the potential of the TTV technique to detect low-mass planets in habitable zones of sun-like stars," said Sun.

By doing so, the TTV method will help further the search for life in the universe, if only in providing more statistics as to the numbers of habitable zone planets that are out there.

The discovery of Kepler-725c was reported on Tuesday (June 3) in the journal Nature Astronomy.

Giant planets are not rare per se — after all, we have four in our own solar system. Such large worlds are, however, rarely found around the smallest stars, red dwarfs. Red dwarfs simply shouldn't have enough material to form such huge worlds.

Well, tell that to the red dwarf star TOI-6894, which is located 238 light-years away. It has just 20% of the mass of the sun, but has been found to host a giant planet, TOI-6894b, that's a little larger than Saturn, albeit with only about half the mass of the ringed planet.

Statistical work has shown that only about 1.5% of red dwarfs harbor gas giant planets, so TOI-6894 is among a rare breed indeed. And it is by far the least massive star to be found with an orbiting giant planet: 60% less massive than the next lowest-mass star with a gas giant.

Given how scarce such worlds around red dwarfs are, finding this new planet in data from NASA's Transiting Exoplanet Survey Satellite (TESS) was not easy. (The "TOI"' in the system's name refers to a "TESS object of interest.")

"I originally searched through TESS observations of more than 91,000 low-mass red dwarf stars looking for giant planets," Edward Bryant of the University of Warwick, who led the discovery, said in a statement.

Upon discovering that TESS had recorded TOI-6894b transiting its star, which gave Bryant the planet's radius, his team then observed it with the ESPRESSO (Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations) spectrograph on the Very Large Telescope in Chile, and SPIRou (Spectropolarimétre Infrarouge) spectrograph on the Canada–France–Hawaii Telescope on Mauna Kea to determine its mass.

However, "we don't really understand how a star with so little mass can form such a massive planet," team-member Vincent Van Eylen of University College London's Mullard Space Science Laboratory said in the statement

There are two models to describe the formation of giant planets. One way, which we think is how Jupiter, Saturn, Uranus and Neptune formed, is via a process called core accretion. A giant planetary core, up to ten times the mass of Earth, forms first out of elements heavier than hydrogen and helium. The gravity of the resulting large rocky body is then able to pull in huge swathes of gas in a runaway process from the surrounding planet-forming disk.

Given that red dwarfs are scaled down stars, the material available in their planet-forming disk is then similarly scaled down — hence why we find many more smaller planets around red dwarfs than gas giants. Calculations suggest the core of TOI-6894b contains 12 times the mass of Earth. However, in a previous survey of 70 planet-forming disks around red dwarfs with between 15 and 25% the mass of our sun, only five were found to contain more than 12 Earth masses of heavy elements, and only one had an abundance significantly greater than 12 Earth masses. The odds are that TOI-6894b shouldn't have been able to support core accretion.

However, Bryant has tried to envisage a process of core accretion by halves. Given that TOI-6894b's overall mass is less than Saturn, a runaway accretion process might not have been required to build up its mass.

"Given the mass of the planet, TOI-6894b could have formed through an intermediate core-accretion process, in which a protoplanet forms and steadily accretes gas without the core becoming massive enough for runaway gas accretion," he said.

An alternative means by which giant planets form is from a disk instability, whereby a section of a planet-forming disk becomes unstable and collapses under its own gravity, coalescing into a planet. This is a top-down formation process rather than the bottom-up of core accretion, but there is disagreement within the astronomical community over whether such low-mass stars can even experience a disk instability.

So, the origin of TOI-6894b remains an open question, but the James Webb Space Telescope (JWST) could potentially discover the answer in the planet's atmosphere.

TOI-6894b orbits close to its star every 3.37 days at a distance of just 3.89 million kilometers (2.42 million miles). A gas giant so close to a sun-like star would be classed as a "hot Jupiter" with an atmospheric temperature in the high hundreds, if not more than a thousand, degrees Celsius. However, as a red dwarf, TOI-6894 is cooler than our sun by more than 2,500 degrees Celsius, meaning TOI-6894b has an atmospheric temperature of just 147 degrees Celsius (296 degrees Fahrenheit) – still warm, but by no means hot. This has repercussions for the chemistry of its atmosphere.

"Based on the stellar irradiation of TOI-6894b, we expect the atmosphere is dominated by methane chemistry, which is very rare to identify," Amaury Triaud of the University of Birmingham said in the statement. "Temperatures are low enough that atmospheric observations could even show us ammonia, which would be the first time it is found in an exoplanet atmosphere."

A proposal to observe TOI-6894b's atmosphere has already been accepted as part of the JWST's fourth cycle of science observations, to take place over the next 12 months. Besides searching for the likes of methane and ammonia, the characteristics of the planet's atmosphere discernible to JWST could point to which formation model – core accretion or disk instability – is the correct one, or even whether a brand new formation model is needed.

Although giant planets around red dwarf stars are rare — other examples include the worlds LHS 3154b, GJ 3512b and c, and TZ Ari b — the numbers may still be on their side. That's because red dwarfs are the most common type of star in the galaxy, making up three-quarters of the estimated 100 billion stars in the Milky Way. So even 1.5% of 75 billion is a huge number of red dwarf stars – 1.125 billion to be exact — that could host giant planets.

"This discovery will be a cornerstone for understanding the extremes of giant planet formation," concluded Bryant.

The discovery of TOI-6894b was published on June 4 in the journal Nature Astronomy.

Humanity's ability to image the heavens has improved by leaps and bounds since the invention of the telescope in 1608. Although the earliest of these images were far from clear, astronomers from generations ago could already observe craters on our moon, identify four of Jupiter's moons, and reveal a diffuse ribbon of light arching across the sky — what we now know represents the Milky Way's structure.

But modern telescopes, like the James Webb Space Telescope (JWST), have really brought the field forward. For instance, telescopes these days rely on very sophisticated instruments called coronagraphs to observe light coming from objects orbiting bright stars. "Current leading coronagraphs, such as the vortex and PIAA coronagraphs, are ingenious designs," Nico Deshler, a Ph.D. student at the University of Arizona and co-author of the new study, told Space.com.

"A coronagraph is an instrument used in astronomy to block or suppress the light coming from a very bright object, like a star, to reveal fainter objects surrounding it." This allows scientists to detect objects more than a billion times fainter than the stars they orbit.

However, Deshler and his colleagues believe they can push coronagraphs further to capture direct images of distant worlds. "Our team is broadly interested in the fundamental limits of sensing and metrology imposed by quantum mechanics, particularly in the context of imaging applications," Itay Ozer, a Ph.D. student at the University of Maryland and another of the study’s co-authors, told Space.com.

The idea is to use principles of quantum mechanics to surpass the resolution limits of current telescopes, allowing scientists to image objects smaller or closer together than what traditional optics would permit.

"The resolution of a telescope generally describes the smallest feature that the telescope can faithfully capture," said Ozer. "This smallest length scale, dubbed the 'diffraction limit,' is related to the wavelength of the detected light divided by the diameter of the telescope."

This means gaining higher resolution requires building larger telescopes. However, launching a telescope large enough to surpass the diffraction limit necessary to directly image an exoplanet poses different types of challenges: high launch costs and extreme engineering complexity.

"In this regard, developing sub-diffraction imaging methods is an important pursuit because it allows us to expand the domain of accessible exoplanets given the challenges and constraints associated with space-based observation," added Deshler. "We were inspired to explore the implications of these newfound quantum information-theoretic limits in the context of sub-diffraction exoplanet imaging where many Earth-like exoplanets are suspected to reside."

The team thus designed a "quantum-level" coronagraph that can sort the light collected by a telescope and isolate the faint signal from exoplanets — light that is usually overwhelmed by the glare of their host stars.

The concept relies on the fact that photons, or particles of light, travel in different patterns known as spatial modes. "In astronomical imaging, the position of each light source in the field of view of a telescope excites different optical spatial modes," explained Ozer.

By using an optical device called a "spatial mode sorter," which is a cascade of carefully designed diffractive phase masks, the team was able to separate the incoming light, allowing them to isolate photons coming specifically from the exoplanet below the sub-diffraction limit. "As light interacts with each mask and propagates downstream through the mode sorter," said Deshler, "the optical field interferes with itself in such a way that the photons in each spatial mode get physically routed to different non-overlapping regions of space."

"The correspondence between the positions of light sources and their corresponding excited spatial modes is central to […] nulling of starlight and detection of exoplanets," added Ozer. "In this way, we are able to siphon the photons emitted by the star away from the photons emitted by the exoplanet."

This goes beyond digitally processing an image and subtracts starlight after the fact — in other words, it removes starlight in the optical domain before the light even reaches a detector. "In exoplanet searches, a telescope is rotated to point directly at a prospective star, which we model as a point source of light," explained Deshler. "Under this alignment between the star and the telescope axis, all the photons emanating from the star couple to the [telescope’s] fundamental mode — the specific spatial mode that is excited when looking at an on-axis point source."

Under this alignment, all the photons emanating from the star couple to the fundamental mode. By filtering out this mode, Deshler, Ozer and their colleagues were able to effectively eliminate the starlight, revealing only the light from the exoplanet.

"The exoplanet's light is misaligned to the telescope axis, and excites a different spatial mode from the star,” said Ozer. "Our method preserves as much of the pristine uncontaminated photons from the exoplanet as possible, which turn out to carry all the available information."

In the lab, the team set out to show that their device could detect exoplanets positioned extremely close to their host stars — closer than traditional resolution limits allow. They tested it using two points of light: a bright one to represent the star and a much dimmer one to simulate an exoplanet. By gradually moving the dimmer light and recording the resulting images, they assessed how well the device could localize the exoplanet.

They found that when the artificial exoplanet was very close to the star — less than one-tenth the separation limit of current telescopes — most of its photons were filtered out along with the starlight. At larger separations, however, the exoplanet's signal became clearer, rising above background noise and aligning with theoretical predictions.

Additionally, by setting the star to be 1,000 times brighter than the planet and analyzing the images with a maximum likelihood estimator, the team achieved results within a few percent of the theoretical limit across a wide range of sub-diffraction planet positions.

"This is a proof-of-principle demonstration that spatial mode sorting coronagraphs may provide access to deeply sub-diffraction exoplanets which lie beyond reach for current state-of-the-art systems," said Deshler. "We are hopeful that this method might allow astronomers to push the boundaries of exoplanets accessible with direct imaging."

The team says the technology needed to build and implement their quantum-optimized coronagraph already exists. They're now working to refine the device into a deployable system that meets performance targets.

"The main limitation is the fidelity of the mode sorter," explained Ozer. "In the lab, we measure the 'purity' of the modes through a metric called the cross-talk matrix, which describes the undesired photon leakage that occurs between independent modes. Cross-talk is largely induced by manufacturing imperfections and small experimental misalignments. To successfully image Exo-Earths, […] the mode sorter must isolate each photon in the fundamental mode to better than one part in a billion if the exoplanet is to be resolved."

The team says precision manufacturing is necessary to fabricate high-quality phase masks that can meet these "cross-talk" requirements. "We envision the use of advanced techniques, such as photolithography, additive manufacturing, or micromachining, to construct extremely precise diffractive surfaces," Deshler said.

The duo hopes this technology will one day provide complementary data for future flagship telescope missions like the Habitable Worlds Observatory, a proposed successor to the Hubble Space Telescope, the JWST, and the Nancy Grace Roman Space Telescope.

"Direct imaging is one of the few observation strategies that can measure the wavelength spectrum of an exoplanet," explained Ozer. "In turn this spectrum may contain clues about atmospheric composition of an exoplanet and reveal potential chemical biosignatures."

"We imagine that mode-sorter driven coronagraphs could augment the astronomy toolkit and enable better characterization of sub-diffraction exoplanets," added Deshler. "However, the difficulty of exoplanet discovery warrants cross-validation with a multiplicity of observational techniques such as transits, velocimetry, and gravitational microlensing. Therefore, this technology is by no means a one-size-fits-all solution."

The study was published on April 22 in the journal Optica.