Overview
- A paper published in Science on Thursday reports a robust helium absorption signal from LHS 1140 b’s upper atmosphere, which the authors describe as the first clear atmospheric detection for a rocky planet in another star’s habitable zone.
- The signal was found using the WINERED spectrograph on the Magellan Clay telescope after a model by lead author Collin Cherubim predicted an escaping, helium‑rich upper atmosphere for this world.
- The detection comes from a strong helium signature in 2024 observations while a 2025 observation showed no helium, so researchers say multi‑epoch replication is needed to confirm variability versus observational effects.
- Helium traces the extended, escaping upper atmosphere and does not reveal the lower atmosphere or surface conditions, so JWST and other follow‑up campaigns are planned to search for water, CO2, and other gases.
- The result shows some rocky planets around red dwarfs can hold atmospheric material for billions of years, broadens the pool of nearby targets for habitability studies, and notes that LHS 1140 c showed no atmospheric signal in the same survey.