Astronomers have confirmed the first atmosphere on a rocky, Earth-like planet within a star’s habitable zone. The exoplanet, LHS 1140b, orbits a red dwarf 48 light-years away. Recent observations suggest the planet may possess a helium-dominated atmosphere, marking a significant advancement in the search for potentially habitable worlds beyond our solar system.
LHS 1140b: A Rocky World in the Goldilocks Zone
LHS 1140b, discovered in 2017, sits approximately 48 light-years from Earth in the constellation Cetus. Orbiting an inactive M-dwarf star, the planet has garnered intense scientific interest because it occupies the Goldilocks zone
—the distance where temperatures are theoretically temperate enough for liquid water to exist on the surface.
The planet is approximately 5.6 times the mass of Earth with a radius 70% larger than our own. While it is tidally locked—meaning one side faces its star in eternal daylight while the other remains in darkness—researchers believe its composition and temperature profile make it a primary laboratory for astrobiology.
Detecting Helium and the Challenge of Atmospheric Escape
The identification of an atmosphere on a rocky planet orbiting a red dwarf is a milestone because these stars are notoriously volatile. They frequently emit high-energy radiation and solar flares that typically strip atmospheres away from nearby planets over time. Data captured in 2024 revealed the presence of escaping helium, providing direct evidence of an atmospheric envelope.
For more on this story, see Astronomers Discover Massive “Silk Planet”: A Giant World as Light as a Cloud.
However, the findings have introduced new questions about the nature of this atmosphere. Observations taken in 2025 did not show the same helium signal, leading researchers to conclude that the atmospheric escape may be variable. Dr.
“Because there’s helium there, and because the helium is escaping, the question is: Is it a bare rock with no atmosphere that sometimes burps up some gas that then immediately escapes, or is there a steady-state atmosphere there that will leak out stuff like the Earth does from time to time?”
Dr. Jason Dittmann, astronomer at the University of Florida, via Mashable
Comparing LHS 1140b to Other Candidates
The scientific community has long searched for Earth 2.0, with various systems like TRAPPIST-1 and GJ 251c drawing significant attention. Unlike LHS 1140b, observations of the inner planets of the TRAPPIST-1 system—conducted with the James Webb Space Telescope—have yet to yield definitive evidence of an atmosphere.
The discovery at LHS 1140b stands apart because the signal was strong enough to be confirmed through rigorous spectroscopic analysis.
Future Observations and the Search for Life
The next phase of research will focus on determining if the atmosphere contains more than just helium. The research team emphasizes that while the presence of an atmosphere is a necessary condition for life, it does not confirm the existence of biological processes.
This follows our earlier report, A Jupiter-size planet that escaped its star’s death.
The discovery also informs the broader strategy for finding habitable worlds. By confirming that at least one rocky planet around a red dwarf can survive the harsh radiation of its host, astronomers have a clearer target for future missions. As the scientific community prepares for the next generation of space observatories, the focus on LHS 1140b is expected to intensify, potentially providing the most detailed look yet at an environment that may mirror our own planet’s early conditions.
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