Scientists have directly detected helium in the atmosphere of LHS 1140 b, a rocky planet located 48 light-years from Earth. The finding is significant because the planet orbits within its star’s habitable zone, where liquid water could potentially persist on the surface.
The evidence suggests that LHS 1140 b has not lost its atmospheric envelope despite orbiting a red dwarf. Such stars can produce intense radiation, stellar flares, and coronal mass ejections that may gradually strip gas from nearby planets.
LHS 1140 b is described as the first rocky exoplanet with a directly detected atmosphere that also lies in a habitable zone. The direct helium signal offers scientists a rare way to investigate the environment of a distant rocky world.
A Difficult Environment for Atmospheres
Red dwarfs are the most common type of star in the universe, but their activity complicates the search for habitable planets. A planet close enough to receive suitable temperatures may also face radiation that threatens its atmosphere over long periods.
The apparent survival of the atmosphere around LHS 1140 b therefore carries particular weight. It indicates that at least one rocky planet may be able to retain a gaseous layer for billions of years near a red dwarf.
Collin Cherubim, the lead author of the study and a recent Harvard University Ph.D. graduate, emphasized the importance of the detection. He said the team had directly detected helium in the atmosphere, describing it as the first direct detection for any rocky exoplanet.
Cherubim also told Live Science that the result matters because LHS 1140 b’s atmosphere has not disappeared in a red-dwarf environment. The finding does not establish that the planet hosts life, but it strengthens the case for further investigation.
| Object | Known Characteristics | Why It Matters |
|---|---|---|
| LHS 1140 b | Rocky planet, 48 light-years away | Helium detected in its atmosphere |
| Host star | Red dwarf, about one-third the size of the Sun | Allows a relatively close orbit |
| Planetary orbit | Within the habitable zone | Could support conditions for liquid water |
Why the Orbit Is Promising
The planet circles a red dwarf that is smaller and cooler than the Sun. Its relatively close orbit is needed to receive conditions suitable for temperatures associated with liquid water.
Being close to its star does not automatically make LHS 1140 b too hot. Its position places it in the habitable zone, often called the Goldilocks zone, where an orbit is neither too hot nor too cold for liquid water.
Scientists estimate that the planet is rocky and may have an iron core. Together with its atmosphere and temperature conditions, these traits make it a notable target in the search for potentially habitable rocky planets.
However, LHS 1140 b is not an identical copy of Earth. Current observations do not confirm the presence of liquid water on its surface, nor do they provide evidence that life exists there.
More Observations Are Needed
Exoplanets are planets beyond the Solar System, and the number of confirmed discoveries has surpassed 6,000. Yet detecting an atmosphere around a rocky exoplanet remains difficult, particularly around active red dwarfs.
LHS 1140 b was first discovered in 2017 by a team led by astronomer Jason Dittmann. Dittmann, now a co-author of the latest finding, noted that certainty about the atmosphere only became possible as observations and analytical capabilities improved.
The next stage of research will focus on the atmosphere’s composition and the planet’s surface conditions. Those measurements will be essential for determining how favorable this distant world may be for habitability.