Rocky planet with atmosphere confirmed in habitable zone, 48 light-years away

Astronomers have detected an atmosphere on LHS 1140b, a rocky planet 48 light-years away in the habitable zone of a red dwarf star. The discovery, confirmed through helium signatures observed in 2024 and 2025, marks the first confirmed atmosphere on a potentially habitable rocky exoplanet, though further observations are needed to determine if liquid water or other life-supporting conditions exist.

Quick Facts

Detection of helium in upper atmosphere of rocky exoplanet
Confirmation of atmosphere on rocky planet in habitable zone
Transit spectroscopy observations using near-infrared spectrograph
Atmospheric escape measurements between 2024 and 2025
Publication of findings in Science journal

Astronomers have confirmed the first detection of an atmosphere around a rocky planet located in the habitable zone of a distant star. The planet, LHS 1140b, orbits a red dwarf approximately 48 light-years from Earth and was observed using the Magellan Clay Telescope at Las Campanas Observatory in Chile.

The discovery was made by detecting helium in the planet's upper atmosphere during transit observations in 2024 and 2025. Helium signatures appeared in 2024 observations but were not recovered in 2025, suggesting variability in atmospheric escape. The helium detection indicates that the planet retains a substantial atmosphere despite atmospheric loss over billions of years. The research team, led by Collin Cherubim of Harvard University, published their findings in the journal Science on 16 July 2026.

LHS 1140b meets three key criteria for potential habitability: it is a rocky super-Earth with a mass of 5.6 Earth masses and radius of 1.73 Earth radii; it orbits within the habitable zone of its star, where temperatures could permit liquid water; and it possesses a detectable atmosphere. Climate modelling suggests the planet's lower atmosphere may contain heavier gases such as nitrogen, carbon dioxide, and carbon monoxide. Estimates indicate water could comprise 9 to 19 percent of the planet's mass, consistent with a possible subsurface ocean.

The planet's older, relatively quiet red dwarf host star produces less high-energy radiation than many comparable stars, which may have aided atmospheric retention. James Webb Space Telescope observations previously ruled out a thick hydrogen-rich atmosphere. The stronger surface gravity of LHS 1140b compared to Earth improves its capacity to retain heavier atmospheric constituents despite ongoing helium loss.

The research confirms the detection technique and opens pathways for future study with more advanced instruments. However, the helium detection does not yet establish the presence of liquid water, the composition of the lower atmosphere, or habitability. More than 6,200 exoplanets have been discovered since 1992, but LHS 1140b is the first rocky planet in a habitable zone shown to retain an atmosphere.

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Technology Space and Moon Landing World Science

#habitable zone #astrobiology #atmosphere detection #helium spectroscopy #LHS 1140b #transit spectroscopy #rocky planet #habitability #exoplanet

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Why This Matters

The confirmation of an atmosphere on a rocky exoplanet in a habitable zone marks a methodological milestone in exoplanet characterization: it demonstrates that transit spectroscopy can detect atmospheric retention on potentially habitable worlds beyond our solar system. This opens a measurable pathway for future surveys to assess atmospheric composition, water presence, and habitability signatures on similar rocky planets. The discovery affects research priorities for space telescope missions planning follow-up observations and shapes scientific understanding of atmospheric evolution timescales around red dwarf stars.

Timeline & Sources

Jan 1, 2017

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LHS 1140b discovered

Jan 1, 2025

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Follow-up observations conducted; helium signal not recovered, indicating variable atmospheric escape