A Rocky World 48 Light-Years Away Appears to Have Kept an Atmosphere
Astronomers detected helium escaping from LHS 1140 b, providing strong evidence that this rocky planet in its star’s habitable zone retains an atmosphere. The finding makes it an exceptional target for follow-up observations, but it does not demonstrate liquid water, an Earth-like climate or life.
Verified topics and entities
Astronomers have found a faint helium signature around LHS 1140 b, a rocky planet about 48 light-years away. The signal indicates that the world has retained an atmosphere while orbiting inside the temperate region around its red-dwarf star.
The 30-second summary
- What happened? Spectra recorded during a transit revealed helium escaping from LHS 1140 b.
- Why does it matter? Keeping an atmosphere is a prerequisite for a stable climate and makes the planet unusually valuable for further study.
- What is the catch? An atmosphere is not evidence of oceans, Earth-like conditions or life, and the helium signal varied between observing years.
KEY NUMBER
LHS 1140 b lies about 48 light-years from Earth and is roughly 5.6 times Earth’s mass.
How astronomers found an atmosphere they could not see
The team used the WINERED spectrograph on the Magellan Clay telescope in Chile while the planet crossed its star. Starlight passing near the planet showed absorption associated with helium escaping from its upper atmosphere.
A nearby planet transited on the same night but showed no comparable helium signal, providing a useful control. The detection appeared in 2024 data, although it was not repeated in 2025, possibly because atmospheric escape varies.
Why LHS 1140 b stands out
The planet is rocky and orbits in the habitable zone, where temperatures may permit liquid water under suitable atmospheric conditions. Models suggest it has retained gas for billions of years despite orbiting a red dwarf.
Helium reveals that an atmosphere exists, but not what dominates its lower layers. Nitrogen, carbon dioxide, pressure, clouds and surface temperature remain unknown.
Before we overstate the result
- The habitable zone describes stellar heating, not confirmed habitability.
- No water, biological molecule or evidence of life was detected.
- The escaping upper atmosphere may not represent conditions near the surface.
- The signal’s year-to-year variability requires further observation.
What happens next
Astronomers will seek repeated helium detections and measurements of heavier gases. LHS 1140 b is not a second Earth, but it is now one of the best laboratories for learning whether rocky worlds around red dwarfs can preserve atmospheres.
Sources and citations4 sources
External references used to support the reporting in this article.
Published by
NewTqnia Space Desk
An institutional editorial team within NewTqnia
