Rocky Exoplanet LHS 1140b Found to Have Atmosphere

Astronomers have for the first time detected an atmosphere surrounding a rocky exoplanet orbiting within the habitable zone of its star, a landmark discovery that significantly advances the search for potentially habitable worlds beyond our solar system. The findings, published on July 16, 2026, in the journal Science, focus on the planet LHS 1140b, located approximately 48 to 50 light-years from Earth.

The planet, about 5.6 times more massive and 1.73 times larger than Earth, orbits a small, cool M dwarf star. Its location within the habitable zone means surface temperatures could theoretically allow for liquid water. The detection of an atmosphere, a critical component for life as we know it, moves this world from a candidate to a prime target for astrobiological study.

Researchers led by Collin Cherubim, now a NASA Hubble Fellow at the University of Chicago, made the discovery by observing helium gas escaping from the planet's upper atmosphere. The team used the Warm Infrared Echelle (WINERED) Spectrograph on the Magellan Clay telescope at Las Campanas Observatory in Chile during observations in 2024. They detected a spectral signal indicating excited helium atoms, which they...