3 min readJul 17, 2026 08:52 PM IST
Astronomers have detected an atmosphere around a rocky planet located about 49 light-years from Earth, marking what researchers describe as the clearest evidence yet that a potentially habitable exoplanet can retain an atmosphere.
The planet, LHS 1140b, lies within its star’s habitable zone, the region where temperatures could allow liquid water to exist on the surface. While scientists stress there is no evidence of life, the discovery suggests the planet possesses several key ingredients considered key for habitability.
The findings, published in the journal Science on July 16, represent the first confirmed detection of an atmosphere on a rocky planet considered potentially suitable for life.
LHS 1140b was first discovered in 2017. It is larger and has more mass than Earth but cooler, and orbits a relatively calm red dwarf star once every 25 days. Unlike Earth, the planet is tidally locked, meaning one side permanently faces its star while the other remains in constant darkness. This means there is no night and day.
Using observations from the Las Campanas Observatory in Chile, researchers detected helium escaping from the planet’s upper atmosphere in 2024. The escaping helium provided strong evidence that LHS 1140b possesses a helium-rich atmosphere, something scientists had previously predicted through theoretical models.
Collin Cherubim, a planetary scientist at Harvard University and one of the study’s researchers, said the planet appears to have the essential conditions required for habitability, even though no biological signatures have been detected.
Scientists have long known that large gas giants can retain atmospheres, but proving the same for rocky planets has been much more difficult because of their smaller size and weaker signals.
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The discovery is especially significant because LHS 1140b orbits a red dwarf, the most common type of star in the Milky Way. Although these stars often emit intense flares capable of stripping away planetary atmospheres, LHS 1140b’s host star appears to be less active than most, improving the planet’s chances of maintaining its atmosphere over billions of years.
Interestingly, follow-up observations in 2025 did not detect escaping helium, suggesting the planet’s atmosphere may change over time. Researchers say this is the first time atmospheric change has been seen on a rocky exoplanet.
Despite being described as Earth-like, LHS 1140b differs significantly from our planet. Its year lasts just 25 Earth days, it has no regular day-night cycle, and its atmosphere is believed to be dominated by helium rather than nitrogen.
Researchers believe the discovery is an important step toward identifying truly Earth-like worlds and understanding how common potentially habitable planets may be throughout the galaxy. While LHS 1140b is not confirmed to host life, its atmosphere makes it one of the most promising targets for future observations searching for signs of biological activity.
