Astronomers Detect Atmosphere on Rocky Exoplanet LHS 1140 b

Astronomers have detected an atmosphere on the rocky exoplanet LHS 1140 b, located 48 light-years from Earth. Spectral analysis of observations taken in 2024 and 2025 showed helium escaping from the planet, which researchers modeled to confirm the atmosphere's presence. The findings were published this week in the journal Science.

LHS 1140 b is the first exoplanet observed to combine a rocky composition, a position inside the habitable zone of its star, and retention of an atmosphere. The planet orbits a cool red dwarf star and was first identified in 2017. Data indicate the atmosphere has persisted for at least three billion years.

It differs from Earth's, with possible heavier gases such as nitrogen or carbon dioxide concentrated in lower layers. Researchers stated that more powerful instruments will be required to determine whether surface oceans or other habitable features exist on LHS 1140 b.

Robin Wordsworth, a Harvard professor and one of the study's authors, said: "Twenty years ago we wondered whether other terrestrial-type planets even existed.

Then we learned they're common, and found some in the habitable zone. The next question was whether any of them had managed to keep an atmosphere. " The detection technique will be applied to additional targets as telescope capabilities advance.