SPACE/COSMOS
Detected: Rocky, habitable-zone exoplanet with an atmosphere
A team of astronomers has detected evidence of an atmosphere on a rocky planet orbiting in the habitable zone of its host star.
image:
In this artist’s concept, the exoplanet LHS 1140 b is shown in the foreground, surrounded by a helium-rich atmosphere. Another nearby rocky planet orbits the same cool red dwarf star in the distance. A new study provides the strongest evidence yet that LHS 1140 b has retained an atmosphere, representing a milestone step toward the discovery of Earth-like rocky planets beyond our solar system.
view moreCredit: Melissa Weiss/Center for Astrophysics |Harvard & Smithsonian
Pasadena, CA—A team of scientists led by Harvard University’s Collin Cherubim and including Shreyas Vissapragada and other Carnegie astronomers has detected evidence of an atmosphere on a rocky planet orbiting in the habitable zone of its host star. Until now, the data showing rocky exoplanets with atmospheres has been extremely limited, so this observation—published this week in Science—is a breakthrough in our understanding of these worlds, their life cycles, and their potential habitability.
Theoretical models predict that atmospheres are a critical component for habitability, because they shield a planet from cosmic radiation, enable water to exist on its surface, and regulate dynamic climate cycles that can lead to clement conditions.
Atmospheres have been detected and characterized for hot gas giant planets. However, it has been a technological challenge to confirm the presence of atmospheres on rocky planets that orbit their stars at the right distance to have liquid water—the so-called “habitable zone.” Telescopes, including NASA’s JWST, are actively searching for atmospheres on small, rocky exoplanets, but these observations have mostly revealed airless worlds, making it unclear whether these planets are capable of retaining their atmospheres for long enough to enable life to arise and thrive.
“Red dwarf stars present a good opportunity for this kind of search because they are small and cool, so habitable-zone planets orbiting these stars are relatively accessible using the transit method, where we detect tiny, periodic dips in the host star’s brightness every time the planet passes in front of it from our point of view,” Vissapragada explained. “However, atmospheric signals from species like water and carbon dioxide—usually found in a planet’s lower atmosphere—are extremely subtle and challenging to detect in these habitable-zone planets, even for flagship observatories like the JWST. So, our team decided on a different approach: to search for helium in the upper atmosphere, where signals can be a bit easier to detect.”
On a mission to find a rocky habitable zone planet with evidence of an atmosphere, the research team—which also included Carnegie astronomers Johanna Teske, Nicole Wallack, William Misener, and Andrew McWilliam—zeroed in on a super-Earth called LHS 1140 b.
Discovered in 2017, LHS 1140 b orbits an older red dwarf star over a period of just 24.7 days. It has a mass just 5.6 times that of Earth and a radius about 1.7 times Earth’s. This is consistent with a rocky world that has a bulk composition similar to our own planet’s, making it a good target for the research team’s goals. It receives 42 percent of the stellar radiation that Earth does, enabling the scientists to calculate that its temperature is right for having liquid water, although it is not yet known whether planets in this size range have surfaces like Earth’s.
Using a powerful instrument called the WINERED spectrograph on the world-class Magellan Clay telescope at Carnegie’s Las Campanas Observatory in Chile, the team observed LHS 1140 b in 2024 and saw evidence of helium escaping from its atmosphere—a stunning result.
“This was clear evidence of an atmosphere on a habitable-zone exoplanet,” Vissapragada said. “It was an absolute thrill to see the transit spectra and slowly realize the implications of what we were looking at.”
Spectra are a way of studying a celestial object’s characteristics, including composition, speed, and motion. They take the light emitted by the host star and split it up into its component parts—the same way a prism creates a rainbow. When this light passes through the atmosphere of an exoplanet, astronomers can tell what elements are present there.
“After much careful analysis and consideration of the spectra, we determined that helium was escaping from LHS 1140 b’s atmosphere in 2024 due to heating from stellar X-rays and extreme ultraviolet radiation,” Vissapragada indicated. “However, our 2025 observations revealed no escaping helium, so the atmospheric escape appears to be variable. It is a rare privilege to witness the atmosphere of an extrasolar planet change on such short, human timescales!”
Combined with earlier observations and sophisticated models of exoplanet evolution, the team interpreted these results to indicate the presence of a highly layered atmosphere. They predict the planet has a helium-dominated and hydrogen-poor upper atmosphere, and other chemical species like water are trapped at lower altitudes closer to the surface.
The researchers also observed another planet in the same system, LHS 1140 c, which is both smaller and more highly irradiated. There was no evidence of an atmosphere, perhaps indicating that these two worlds may fall on opposite sides of the so-called “cosmic shoreline.” On one side are planets that retain their atmospheres for billions of years, and on the other those with atmospheres that boil off quickly into space.
This exciting discovery is just one of many Carnegie-led and co-led projects and investigations of exoplanet atmospheres. Vissapragada, Teske, Wallack, Misener, McWilliam, and many others are using space- and ground-based telescopes, including JWST and the soon-to-launch Nancy Grace Roman Space Telescope, to push the boundaries of exoplanet characterization and understand what could make distant worlds capable of hosting life.
Other members of the LHS 1140 b team include: Tim Cunningham, Annabella G. Meech, David Charbonneau, and Robin Wordsworth from Harvard; Aaron Householder from MIT; Leonardo A. Dos Santos and Mercedes Lopez-Morales from the Space Telescope Science Institute; Zifan Lin from Washington University St. Louis; Michael Zhang from the University of Chicago; and Jason A. Dittmann from University of Florida Gainesville.
Journal
Science
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone
Article Publication Date
16-Jul-2026
First atmosphere detected on a habitable-zone rocky world
Discovery marks major milestone in the search for life on planets beyond our solar system
image:
In this artist’s concept, the exoplanet LHS 1140 b is shown in the foreground, surrounded by a helium-rich atmosphere. Another nearby rocky planet orbits the same cool red dwarf star in the distance. A new study provides the strongest evidence yet that LHS 1140 b has retained an atmosphere, representing a milestone step toward the discovery of Earth-like rocky planets beyond our solar system.
view moreCredit: Credit: Melissa Weiss/CfA
In a major milestone in the search for life on other planets, astronomers have detected, for the first time, an atmosphere surrounding an Earth-like, rocky planet orbiting within the habitable zone of another star.
The finding provides the strongest evidence yet that worlds with conditions similar to Earth in composition and temperature, with the potential to support life, could exist beyond our solar system.
"An atmosphere is essential for a planet to support life as we know it," said lead author Collin Cherubim, who recently earned his Ph.D. in Earth and Planetary Sciences from Harvard University.
"This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star."
Published today in Science, the study reports observational results detecting helium escaping from the atmosphere of LHS 1140 b, a rocky exoplanet about 48 light-years from Earth. Motivated by theoretical predictions, the discovery provides evidence that the planet possesses an atmosphere.
The planet orbits a red dwarf star within the star’s habitable zone, or the region where temperatures and environmental conditions are within the range that could support liquid water on the planet's surface.
Astronomers have discovered thousands of exoplanets, including a few rocky worlds within their stars' habitable zones, but determining whether those planets have atmospheres has remained a great challenge.
"Twenty years ago we wondered whether other terrestrial-type planets even existed,” said Robin Wordsworth, Gordon McKay Professor of Environmental Science and Engineering and Professor of Earth and Planetary Sciences at Harvard and one of Cherubim’s dissertation advisors. “Then we learned they're common, and found some in the habitable zone. The next question was whether any of them had managed to keep an atmosphere. Now we know at least one has."
Although other studies have found rocky planets in the habitable zones of their stars, this study is the first to clearly demonstrate the presence of an atmosphere, one that has existed for billions of years.
Cherubim and his colleagues’ theoretical model predicted that LHS 1140 b has an upper atmosphere rich in helium that is slowly escaping into space.
To test their prediction, the team used the Warm Infrared Echelle (WINERED) Spectrograph on the Magellan Observatory in Chile. They observed a rare alignment, where LHS 1140 b and another planet transited their star on the same night.
Although one planet showed no evidence of an atmosphere, the other, LHS 1140 b, showed helium escaping from around it, confirming that it retains an atmosphere.
Cherubim’s joint advisor David Charbonneau, head of the Harvard Department of Astronomy and astronomer in the Center for Astrophysics | Harvard & Smithsonian, was initially skeptical of Cherubim’s plan because it was the product of a mathematical calculation and had never been observed before for a rocky world.
But when the results came in, he was convinced.
"Collin analyzed the planets we knew about and predicted that this one would have a helium atmosphere,” Charbonneau said. “Then he organized telescope time, got the data, and the detection was statistically rock solid."
The findings suggest that ground-based observations searching for escaping gases may become an important tool for studying atmospheres on rocky exoplanets.
The planet's atmosphere has likely survived for more than three billion years, the astronomers say, making it a valuable target for future observations.
Cherubim said he’d like to determine the atmosphere's full composition and eventually investigate whether the planet has surface oceans or other characteristics associated with habitability. He and his colleagues will also use his model to search for similar worlds.
“This has been a model validation, and hopefully it's just the first of many more observations to come,” he said.
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Journal
Science
Article Title
Escaping helium from a terrestrial planet atmosphere in a nearby habitable-zone
Article Publication Date
16-Jul-2026
New study reveals potential atmosphere on rocky planet of nearby star
Nearly a decade after discovering LHS 1140b, a rocky exoplanet in the habitable zone of a nearby low-mass star, a new study reveals the object may have its own atmosphere.
University of Florida Assistant Professor of Astronomy Jason Dittmann, Ph.D., first discovered the planet in 2016. Now, he is co-author of the new study, published in Science, that uses helium escape to explain a potential atmosphere.
“The exciting part about this paper, and why I think it was accepted into Science, was that this is the first time that we're seeing a rocky, Earth-like planet that could still have an atmosphere.” Dittmann said.
The Magellan Clay telescope at Las Campanas Observatory in Chile showed proof of helium escaping from the planet. However, the planet’s age signals it would have run out of helium unless it was replenishing its own supply, pointing to the potential of an atmosphere.
In 2016, Dittmann used ground-based surveys to search for stars whose light briefly dimmed as orbiting planets passed in front of them.
However, observing from the ground allows for Earth’s atmosphere to confuse this process. To understand if the stars were dimming due to wispy clouds or humidity blowing through on Earth, he trained a machine learning algorithm to decipher which signals were caused by Earth’s weather and which were because of a passing planet.
The method helped Dittmann find LHS 1140b. The planet’s orbit meant it could only be observed a few times a year, so he tried to make the most of the limited opportunities he had to study it.
Considering the type of star it orbits, Dittmann said the planet’s temperature should be similar to Earth’s. It’s made of rock instead of gas, is approximately 40 light years away. There is also a second planet in the system, LHS 1140c, which is located outside the habitable zone of its system.
Other rocky planets discovered within the past decade or so lost their atmospheres over time. Considering the age of LHS 1140b and the lack of atmospheres by similar planets, Dittmann and the team didn’t expect to find helium.
LHS 1140b was different.
“We were getting to the point in the field where maybe all of these planets don't have an atmosphere, and we need to look at ones around sun-like stars instead of smaller stars,” Dittmann said. “And then finally here is actually one with an atmosphere, and it happens to be the one that I had spent so many hours working on.”
After originally discovering the planet, Dittmann quickly requested X-ray data from the planetary system. This gave him the energy input from the star into the planet, which became key to interpreting the helium signal years later.
The Magellan Clay telescope later revealed helium escaping from the planet, a process that also occurs on Earth. The X-ray data explained the rate at which the planet lost its helium because of the X-ray radiation from the host star. Therefore, the X-ray data proved the rocky object must be replenishing its supply of helium; if it wasn’t, there would be no helium remaining.
The team started by asking for helium observations because it is easiest to spot. But now that there is potential proof of an atmosphere, the group of scientists can start looking at carbon dioxide and water to further test the planet’s conditions.
LHS 1140b is one of the current selected targets under the Rocky Worlds Director’s Discretionary Time (DDT) Program. Rocky Worlds DDT is a joint program for the James Webb Space Telescope and the Hubble Space Telescope that is dedicated to finding evidence of atmospheres on rocky exoplanets orbiting dwarf stars.
Dittmann said the Rocky Worlds DDT Program should be able to prove or disprove an atmosphere on LHS 1140b in the next four to five years.
“Because there’s helium there, and because the helium is escaping, the question is: Is it a bare rock with no atmosphere that sometimes burps up some gas that then immediately escapes, or is there a steady-state atmosphere there that will leak out stuff like the Earth does from time to time?” Dittmann said. “JWST data over the next four to five years will look for water, and if there's water in the atmosphere, then it's probably a stable atmosphere that will persist.”
Journal
Science
Method of Research
Data/statistical analysis
Subject of Research
Not applicable
Article Title
Escaping helium from a terrestrial planet atmosphere in a nearby habitable-zone
Article Publication Date
16-Jul-2026
The Sun contains more silver than previously estimated
Uppsala University
image:
The solar spectrum. The two strongest silver lines, highlighted in white, lie in the ultraviolet region that is invisible to the human eye. Image: Anish Amarsi]
view moreCredit: Anish Amarsi/Uppsala University
Researchers at Uppsala University have calculated that the Sun contains 55 per cent more silver than previously estimated. The results are based on more realistic modelling of the Sun’s atmosphere and resolve a long-standing problem of missing silver in the solar system.
Like most stars, the Sun consists almost entirely of hydrogen and helium and only 1.5 per cent of its mass consists of heavier elements such as carbon, iron, or silver. Yet, these trace elements are extremely important. They act as a fossil record of the cosmos.
PhD Student Makes Discovery
“The new knowledge about the Sun’s composition is important for the understanding of other stars, planets and cosmic material, because the Sun is one of astronomy’s key reference points,” says Sema Caliskan, who conducted the work during her PhD studies at the Department of Physics and Astronomy at Uppsala University.
Heavy elements are formed in stars and during stellar explosions and become part of new generations of stars and planets. Mapping the abundance of these elements is key to understanding the chemical evolution of the Milky Way.
Spectroscopic Analysis
To determine the amount of silver in the Sun, the researchers analysed sunlight using spectroscopy. When atoms in the solar atmosphere absorb light, they produce dark absorption features at specific wavelengths in the spectrum, known as spectral lines. These lines act as fingerprints, with each element producing a unique pattern.
The fingerprint is compared to calculated atmospheric models to quantify the abundance of silver in the Sun. Previous estimates were based on simplified models. However, in this new study the researchers developed a new model that predicts 55% more silver than before. They combined a dynamical model of the Sun’s outer layers with improved atomic physics calculations, to capture how silver atoms interact with light and other particles. Unlike earlier methods, the new calculations include non-equilibrium effects, meaning that the light influences the same silver atoms that create the dark absorption lines.
The Solar System’s Missing Silver
“With our new model, we were able to interpret the spectral lines used to determine the solar silver abundance more accurately,” says Sema Caliskan, who started her PhD studies working on the structure of atoms, and later applied her expertise to problems in stellar astrophysics.
The new silver value resolves a long-standing problem of missing silver in the solar system. Until now, the silver abundance measured in the Sun was significantly lower than that found in chemically primitive meteorites, which both formed at the same time from the same cloud of gas and dust 4.6 billion years ago. The new silver value in the Sun is now in much better agreement with these meteorites.
Method Could Be Used on Other Stars
The new results also improve our understanding of how silver and other elements are produced in stars and stellar explosions and later incorporated into new generations of stars and planets. The same method will now be applied to other stars.
“By studying the light of stars of different types and ages, we hope to understand where silver is formed in the universe, and how it has been distributed throughout the Milky Way over time,” says Sema Caliskan.
About the study The calculations were carried out using the Swedish supercomputer Tetralith at the National Supercomputer Centre at Linköping University, bringing together expertise in stellar physics and atomic modelling. Similar methods have been applied to other elements, but this is the first time it has been used to analyse silver in the Sun.
The optical wavelengths (what our eyes see) probe deeper layers of the Sun's atmosphere, and our analysis is based on these layers.
Credit: NASA/GSFC/Solar Dynamics Observatory .
Journal
Astronomy and Astrophysics
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Ag I model atom and the 3D non-LTE solar silver abundance
Article Publication Date
17-Jul-2026
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