Astronomers Confirm the First Atmosphere on a Rocky Exoplanet in the Habitable Zone

Astronomers have confirmed that LHS 1140 b has an atmosphere — specifically a helium-dominated atmosphere — making it the first rocky, Earth-like exoplanet in the habitable zone of its star where an atmosphere has been definitively detected . The finding was published in Science on July 16, 2026, by a team led by Collin Cherubim (Harvard Ph.D. '26) and including co-discoverer Jason Dittmann (University of Florida) .

What Astronomers Confirmed About LHS 1140 b

Using the Magellan Clay telescope in Chile, the team detected helium escaping from the planet . Because LHS 1140 b is old enough that it should have lost all primordial helium long ago, the ongoing helium signal means the planet must be replenishing it — strong indirect evidence of a stable, sustained atmosphere rather than a bare rock .

LHS 1140 b is located about 48 light-years from Earth in the constellation Cetus . It is a super-Earth, roughly 5.6 times the mass of Earth and about 70% larger in radius, orbiting a red dwarf star every 24.7 days . The planet sits squarely in the habitable ("Goldilocks") zone — the region where temperatures could allow liquid water to exist on the surface .

Earlier observations with the James Webb Space Telescope in 2023 had already suggested LHS 1140 b might be a super-Earth ice or water world, possibly an "eyeball planet" with a single liquid ocean surrounded by ice . The new atmospheric detection adds a critical missing piece to the puzzle.

Why This Discovery Is Significant

First-of-its-kind detection

While astronomers have detected atmospheres on many gas giants, this is the first time an atmosphere has been confirmed on a rocky, temperate exoplanet that orbits in the habitable zone . As David Charbonneau, a co-author of the study, said: "People are generally interested in the big questions: Are we alone? Is there life beyond the Earth or beyond our solar system? To that end, this study reveals the first atmosphere discovered on a rocky planet in the habitable zone" .

Sets up a search for life

The planet is rocky, at the right temperature, and now known to have an atmosphere — three of the essential ingredients scientists believe are needed to support life. "All the pieces that we think are essential for life are present," Charbonneau noted .

A window into atmospheric evolution

The detection of helium is telling a deeper story. The fact that the planet's atmosphere is still actively losing helium means the gas must be replenished from below, providing indirect evidence that LHS 1140 b's atmosphere is thick, sustained, and actively cycling — not a thin remnant clinging to a dead world .

The long-awaited goal of exoplanet science

Planets like this have been the holy grail of exoplanet research for decades. "This might be the closest we've gotten to finding a planet that could support life," wrote Space.com in its coverage of the discovery . The discovery moves the conversation from "could such a planet exist?" to "we found one — now what can we learn from it?"

What Comes Next: JWST Follow-Up

LHS 1140 b is already a selected target for the James Webb Space Telescope's Rocky Worlds Director's Discretionary Time Program . Observations over the next 4–5 years will look for water vapor, carbon dioxide, and other molecules that could confirm a stable, life-supporting atmosphere . If water ice or liquid water is detected, LHS 1140 b would become the strongest candidate yet for a habitable world beyond Earth. As the New York Times reported, "At this stage, we have no proof of life existing on this planet" — lead author Collin Cherubim noted — "However, we believe that all the crucial and fundamental components are present" .

The Caveats

Astronomers are careful not to overstate the finding. The atmosphere detected so far is dominated by helium, not oxygen or nitrogen like Earth's. A helium-dominated atmosphere may not be conducive to life as we know it, though it could still support an ocean underneath. There is no evidence of life yet, and it may take years of JWST observations to determine whether the planet is truly habitable .

Why This Matters

LHS 1140 b represents a turning point. For the first time, humanity has direct evidence of an atmosphere on a rocky, temperate planet in another star's habitable zone. Every prior atmospheric detection on a small exoplanet has been ambiguous or contested. This one is clear. If one potentially life-bearing world is out there, countless others could be too — dramatically boosting the odds of extraterrestrial life in the universe .