LHS 1140 b, a super-Earth located 49 light-years away, shows strong evidence of an atmosphere after researchers detected escaping helium. According to a study published Wednesday in Science, the planet orbits within its red dwarf star’s habitable zone, meaning temperatures could allow for liquid water on its surface.
Helium Detection Confirms Atmosphere on LHS 1140 b
An international research team led by Collin Cherubim of Harvard University identified a clear helium signal from the rocky planet in September 2024. This detection, made using a high-resolution spectrograph at the Magellan-Clay Telescope in Chile, suggests the planet possesses a gaseous envelope.
Shreyas Vissapragada of the Carnegie Institution told IFLScience that observing helium escaping from the upper atmosphere is a strong indicator of an atmosphere on a rocky planet in the habitable zone. While the James Webb Telescope provided earlier hints of an air shell, this ground-based observation offers a more concrete signal.
Did you know? LHS 1140 b is classified as a “super-Earth.” It is 1.7 times larger and 5.6 times heavier than Earth, making it a massive rocky world compared to our own.
Atmospheric Volatility and Red Dwarf Radiation
The helium signal did not remain constant. According to the research team, the signal disappeared during a follow-up observation in 2025. Rather than a failure, scientists view this as a discovery: the atmosphere is actively changing.
Researchers attribute this loss to high-energy X-ray and UV radiation from the host star. Because red dwarfs are more active than the Sun, they can “heat away” the upper atmospheres of nearby planets. This creates a central question for astronomers: can planets orbiting red dwarfs—the most common stars in the Milky Way—maintain an atmosphere over billions of years?
Water-World Potential vs. Current Data
The study indicates the upper atmosphere is dominated by helium and contains almost no hydrogen. However, heavier elements like carbon, oxygen, or water may remain trapped in deeper layers. Some previous analyses suggest LHS 1140 b could be a water world, with water accounting for up to 19% of its total mass.
Despite these possibilities, the team is cautious about claims of extraterrestrial life. Vissapragada emphasized to IFLScience that they do not yet know enough about the lower atmosphere to determine its composition, the nature of the surface, or the presence of liquid water. “I want to be very clear: we still have a lot to learn,” Vissapragada stated.
Comparison: LHS 1140 b vs. LHS 1140 c
| Feature | LHS 1140 b | LHS 1140 c |
|---|---|---|
| Atmosphere | Helium detected (variable) | Airless world |
| Habitability | In habitable zone | Hotter |
| Composition | Rocky / Potential Water-World | Smaller |
Future Trends in Exoplanet Research
The contrast between the atmospheric presence on LHS 1140 b and the airless nature of its neighbor, LHS 1140 c, provides a baseline for studying how stellar radiation strips planets of their air. Future observations will focus on the “mysterious fluctuations” of the helium signal to determine if the atmosphere is periodically replenished or steadily eroding.
Pro Tip: To track the latest findings on exoplanets, follow publications in Science and data releases from the James Webb Space Telescope.
Frequently Asked Questions
Is there life on LHS 1140 b?
There is currently no evidence of life. Researchers have only confirmed the presence of an atmosphere via helium detection; they have not yet analyzed the surface or lower atmosphere for biological markers.
How far is LHS 1140 b from Earth?
The planet is located approximately 49 light-years away in the constellation Cetus (Walfisch).
What is a “Super-Earth”?
LHS 1140 b is a super-Earth that is 5.6 times heavier than Earth.
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