LHS 1140b Shows Helium-Rich Rocky Exoplanet Atmosphere

Exam-focused facts from the 22 July 2026 current affairs briefing.

Key facts

Astronomers detected a helium-rich atmosphere around the rocky exoplanet LHS 1140b, which orbits in the habitable zone of a nearby M dwarf star.
The planet has a mass of about 5.6 Earth masses and a radius of 1.73 Earth radii, consistent with an Earth-like composition and a gaseous atmosphere.
The helium atmosphere was observed using the Magellan Clay telescope at Las Campanas Observatory in Chile during the planet's transit across its star.
LHS 1140b is slowly losing its helium atmosphere, but models suggest it could remain stable for over a billion years.
The James Webb Space Telescope (JWST) is planned for follow-up observations to determine the atmosphere's helium content and other molecules.