Chris Smith (KRBwyle)/NASA's Goddard Space Flight Center
An artists's conception shows planet LP 791-18d. The volcanically active planet, which is a similar size to Earth, was discovered by NASA's Spitzer Space Telescope.
NASA, ESA, CSA, Joseph Olmsted (STScI)
This artist's illustration depicts the rocky exoplanet GJ 486 b, which orbits a red dwarf star located 26 light-years away from Earth. Astronomers have detected hints of water vapor in the system, but they can't be sure if it signifies a planetary atmosphere or if it's part of the star.
NASA/JPL-Caltech/Robert Hurt
This illustration shows an Earth-size exoplanet called TOI 700 e, discovered orbiting the small, cool M dwarf star TOI 700, which is located 100 light-years away. Its other Earth-size sibling, TOI 700 d, can be seen in the distance.
NASA's Goddard Space Flight Center
TOI 700 d is the first potentially habitable Earth-size planet spotted by NASA's planet-hunting TESS mission.
Patricia Klein/MPIA
Artist's impression of the exoplanet WASP-121 b. It belongs to the class of hot Jupiters. Due to its proximity to the central star, the planet's rotation is tidally locked to its orbit around it. As a result, one of WASP-121 b's hemispheres always faces the star, heating it to temperatures of up to 3000 degrees Celsius. The night side is always oriented towards cold space, which is why it is 1500 degrees Celsius cooler there.
ESO/L. Calçada
This artist's impression shows a close-up view of Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.
Helena Valenzuela Widerström
The discovery of a second exomoon candidate hints at the possibility that exomoons may be as common as exoplanets.
European Space Agency
This artist's impression shows the football-shaped planet WASP-103b (left) closely orbiting its host star.
Janson et al./ESO
This image shows double-star system b Centauri and its giant planet b Centauri b. The star pair is the bright object at top left. The planet is visible as a bright dot in the lower right. The other bright dot (top right) is a background star.
Adam Makarenko/W. M. Keck Observatory
This artist's rendering shows a Jupiter-like planet orbiting a dead white dwarf star 6,500 light-years away from Earth. The planet survived the violent phases of stellar evolution leading to the star's death.
M. Kornmesser/ESO
This artist's illustration shows the night-side view of the exoplanet WASP-76b, where iron rains down from the sky.
Amanda Smith/University of Cambridge
Astronomers have identified a new class of habitable planets, which they call Hycean planets. These are hot, ocean-covered planets with hydrogen-rich atmospheres.
M. Kornmesser/ESO
This artist's illustration shows L 98-59b, one of the planets in a planetary system 35 light-years away from Earth. This planet has half the mass of Venus.
Scott Wiessinger/NASA
In this artist's illustration, two gaseous exoplanets can be seen orbiting the bright sun-like star HD 152843.
JPL-Caltech/NASA
An artist's rendering of TOI-1231 b, a Neptune-like planet about 90 light years away from Earth.
From NRAO/S. Dagnello
This artist's conception depicts a violent flare erupting on the star Proxima Centauri as seen from the viewpoint of a planet orbiting the star called Proxima Centauri b.
NASA/ESA/R. Hurt
After losing its gaseous envelope, the Earth-size core of an exoplanet formed a second atmosphere. It's a toxic blend of hydrogen, methane, and hydrogen cyanide that is likely fueled by volcanic activity occurring beneath a thin crust, leading to its cracked appearance.
NASA/JPL-Caltech
This illustration shows the metaphorical measuring of the density of each of the seven planets in the nearby TRAPPIST-1 system. New measurements have revealed the most precise densities yet for these planets and they're very similar -- which means they also likely have similar compositions.
L. Calçada/ESO
This artist's illustration shows the view from the furthest planet in the TOI-178 system.
W. M. Keck Observatory/Adam Makarenko
This artist's illustration shows TOI-561b, one of the oldest and most metal-poor planetary systems discovered yet in the Milky Way galaxy. Astronomers found a super-Earth and two other planets orbiting the star.
ESA/Hubble/M. Kornmesser
This massive and distant exoplanet, called HD106906 b, has an elongated and angled orbit that causes it to take 15,000 Earth years to complete one lap around its twin stars.
Jan Skowron/Astronomical Observatory, University of Warsaw
This is an artist's impression of a free-floating rogue planet being detected in our Milky Way galaxy using a technique called microlensing. Microlensing occurs when an object in space can warp space-time.
ESA
This is an artist's impression of exoplanet WASP-189 b orbiting its host star. The star appears to glow blue because it's more than 2,000 degrees hotter than our sun. The planet, which is slightly larger than Jupiter, has a tilted orbit around the star's poles rather than its equator.
NASA's Goddard Space Flight Ce
For the first time, an exoplanet has been found orbiting a dead star known as a white dwarf. In this artist's illustration, the Jupiter-sized planet WD 1856 b orbits the white dwarf every day and a half.
Shim/ASU/Vecteezy
This illustration shows a carbon-rich planet with diamond and silica as ts main minerals. Water can convert a carbon-rich planet into one that's made of diamonds. In the interior, the main minerals would be diamond and silica (a layer with crystals in the illustration). The core (dark blue) might be made of an iron-carbon alloy.
European Southern Observatory/Bohn et al.
This image shows a young sun-like star being orbited by two gas giant exoplanets. It was taken by the SPHERE instrument on European Southern Observatory's Very Large Telescope. The star can be seen in the top left corner, and the planets are the two bright dots.
Mark Garlick/University of Warwick
This artist's impression shows a Neptune-sized planet in the Neptunian Desert. It is extremely rare to find an object of this size and density so close to its star.
Mark Garlick
This is an artist's impression of the multiplanetary system of newly discovered super-Earths orbiting a nearby red dwarf star called Gliese 887.
NASA's Goddard Space Flight Center/Chris Smith (USRA)
The newly discovered exoplanet AU Mic b is about the size of Neptune.
European Southern Observatory/M. Kornmesser
This artist's impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Proxima b is a little more massive than the Earth.
Jack Madden/Carl Sagan Institute/Cornell University
This is an artist's illustration of an exoplanet's atmosphere with a white dwarf star visible on the horizon. The starlight of a white dwarf filtered through the atmosphere of an exoplanet that's orbiting it could reveal if the planet has biosignatures.
Adam Makarenko/W. M. Keck Observatory
This is an artist's illustration of the Kepler-88 planetary system, where one giant exoplanet and two smaller planets orbit the Kepler-88 star. The system is more than 1,200 light-years away.

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The James Webb Space Telescope has detected water vapor around a rocky exoplanet that orbits a star located 26 light-years away from Earth.

Now, astronomers are trying to determine whether that water vapor is an indicator of what would be the first-known presence of an atmosphere around a rocky exoplanet.

Small, cool red dwarf stars are the most common stars in the universe. The exoplanets found in the “habitable zone” — the perfect distance from a star to allow the planet to be warm enough to host liquid water on its surface — often orbit red dwarfs very closely since they aren’t as warm as the sun.

NASA/ESA/CSA
Based on new evidence from the NASA/ESA/CSA James Webb Space Telescope, this illustration reflects the conclusion that the exoplanet LHS 475 b is rocky and almost precisely the same size as Earth. The planet whips around its star in just two days, far faster than any planet in the Solar System. Researchers will follow up this summer with additional observations with Webb, which they hope will allow them to definitively conclude if the planet has an atmosphere. LHS 475 b is relatively close, 41 light-years away, in the constellation Octans. [Image Description: Illustration of a planet and its star on a black background. The planet is large, in the foreground at the centre, and the star is smaller, in the background and also at the centre. The planet is rocky. The top quarter of the planet (the side facing the star) is lit, while the rest is in shadow. The star is bright yellowish-white, with no clear features.]

James Webb Space Telescope discovers its first exoplanet

Red dwarf stars lash out with ultraviolet and X-ray radiation that has the potential to demolish fragile layers of gas, leading scientists to question whether rocky planets orbiting them can maintain — or regain — atmospheres.

Astronomers observed a hot, rocky exoplanet called GJ 486 b using the Webb telescope. The planet is about 30% larger than Earth and has much stronger surface gravity than our planet.

The planet is so close to its host star that GJ 486 b completes one orbit around it every 1.5 Earth days, and this proximity heats the planet to a surface temperature of 800 degrees Fahrenheit (430 degrees Celsius). Astronomers believe the planet is tidally locked, meaning that one side always faces the star while the other is a permanent night side — similar to how the moon orbits Earth.

Although the scorching temperatures make the planet too hot to be habitable, observations of GJ 486 b with Webb’s Near-Infrared Spectrograph revealed hints of water vapor. A study detailing the findings has been accepted for publication in The Astrophysical Journal Letters.

The presence of water vapor could suggest that GJ 486 b somehow has an atmosphere, despite its heat and proximity to the star.

NASA

Webb telescope captures its first direct image of an exoplanet

Water vapor mystery

While water vapor has previously been detected on gaseous exoplanets, scientists have yet to find an atmosphere around a rocky exoplanet — doing so would be a landmark event, since that would make it similar in a way to planets in our solar system like Earth and Mars, which are considered rocky.

“Water vapor in an atmosphere on a hot rocky planet would represent a major breakthrough for exoplanet science. But we must be careful and make sure that the star is not the culprit,” said study coauthor Kevin Stevenson, principal investigator on the Webb observing program at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, in a statement.

The team observing GJ 486 b watched as the planet crossed in front of its star twice, and then they used multiple methods to analyze the data captured by the telescope’s instruments.

When planets pass in front of their stars, also known as a transit, the starlight can filter through a planet’s atmosphere and highlight the chemical traces of different gases and elements. The results from the Webb data analysis pointed to water vapor being present around GJ 486 b.

But astronomers are taking care with their interpretation of the findings because it’s possible that the water vapor is connected to the star itself.

NASA, ESA, CSA, and J. Olmsted (STScI)

NASA's Webb telescope captures first evidence of carbon dioxide on an exoplanet

“We see a signal, and it’s almost certainly due to water. But we can’t tell yet if that water is part of the planet’s atmosphere, meaning the planet has an atmosphere, or if we’re just seeing a water signature coming from the star,” said lead study author Sarah Moran, postdoctoral research associate at the University of Arizona in Tucson, in a statement.

NASA, ESA, CSA, Joseph Olmsted (STScI)
This graphic shows the data collected by the Webb telescope as it observed GJ 486 b.

Water vapor even exists on our sun in sunspot regions. Sunspots or starspots are areas that appear dark on stars because they’re cooler than other parts of the surface.

Since the red dwarf star hosting GJ 486 b is much smaller and cooler than the sun, it may contain even more water vapor in its starspots — enough to create a signal that could be misinterpreted as a planetary atmosphere surrounding the closely orbiting exoplanet, according to the researchers.

“We didn’t observe evidence of the planet crossing any starspots during the transits. But that doesn’t mean that there aren’t spots elsewhere on the star. And that’s exactly the physical scenario that would imprint this water signal into the data and could wind up looking like a planetary atmosphere,” said study coauthor Ryan MacDonald, a NASA Sagan Fellow at the University of Michigan in Ann Arbor, in a statement.

M. Kornmesser/European Southern Observatory
This artist's impression shows an ultra-hot exoplanet, a planet beyond our Solar System, as it is about to transit in front of its host star. When the light from the star passes through the planet's atmosphere, it is filtered by the chemical elements and molecules in the gaseous layer. With sensitive instruments, the signatures of those elements and molecules can be observed from Earth. Using the ESPRESSO instrument of ESO's Very Large Telescope, astronomers have found the heaviest element yet in an exoplanet's atmosphere, barium, in the two ultra-hot Jupiters WASP-76 b and WASP-121 b.

Astronomers detect heaviest element ever found in exoplanet atmospheres

The heat and radiation from the star would likely erode GJ 486 b’s potential atmosphere over time. If the exoplanet currently has an atmosphere, it would need replenishment from a constant source, like steam from volcanoes.

Future observations of the planet using different instruments on the Webb telescope could reveal additional details about the source of the water vapor.

“It’s joining multiple instruments together that will really pin down whether or not this planet has an atmosphere,” Stevenson said.