Helium Leak Confirms Atmosphere on a Habitable-Zone Rocky Planet

Astronomers have found more than 6,000 planets orbiting other stars, many of them small and rocky like Earth. But firm evidence that any of them host stable atmospheres has, despite years of searching, remained elusive. That may have just changed.

Astronomers have identified what they say is the first confirmed atmosphere surrounding a rocky planet inside a habitable zone beyond our solar system. The planet, LHS 1140b, sits about 49 light-years (roughly 460 trillion kilometers) from Earth and appears to have three key ingredients scientists consider necessary for a potentially habitable environment: a solid, rocky surface, temperatures that can support liquid water, and now, an atmosphere.

Using spectral data from the Magellan Clay telescope at Las Campanas Observatory, astronomers detected helium escaping from LHS 1140b, a rocky exoplanet orbiting in the habitable zone of the nearby low-mass star LHS 1140. The escape of helium is, counterintuitively, the good news here. X-ray data revealed the rate at which the planet loses helium due to radiation from its host star, and the calculation proved the rocky object must be actively replenishing its supply; if it weren't, no helium would remain at all.

The planet was first identified in 2016 by Jason Dittmann, an assistant professor of astronomy at the University of Florida. Dittmann described the find as a turning point: after years of accumulating evidence that planets like this probably couldn't hold atmospheres, the one world that proved otherwise turned out to be the very planet he had spent years studying.

Run jointly by the James Webb Space Telescope and Hubble Space Telescope, the Rocky Worlds Director's Discretionary Time Program searches for evidence of atmospheres on rocky exoplanets orbiting dwarf stars, and LHS 1140b is among its selected targets. Upcoming observations will search for water and carbon dioxide to test for a stable, potentially long-lived atmosphere in the habitable zone.

A planet leaking helium turns out to be the most hopeful thing we've heard all year.

Read the full story at University of Florida News, July 16, 2026

Hot Take: 49 light-years away, a rocky planet has been quietly hissing helium into space like a balloon with a slow leak. That hiss is the first confirmed breath of a habitable-zone world.