A landmark observation confirms an atmosphere on rocky exoplanet LHS 1140 b, including evidence that helium is escaping from the planet’s upper layers, based on 2024 transits with the Magellan Clay telescope.

This finding demonstrates that rocky worlds orbiting dwarf stars can retain atmospheres, a crucial factor in evaluating habitability, potential liquid water, and biosignature prospects.

LHS 1140 b, about 48 light-years away, is identified as Earth-like in habitability terms, with the potential for liquid water and a protective atmosphere, making it a leading target for astrobiology.

unpublished JWST data could help determine the atmosphere’s bulk composition and size, clarifying habitability prospects.

Planned JWST follow-ups aim to quantify atmospheric composition, including helium abundance and other molecules, to confirm the atmosphere.

Models and observations point to a helium component in the atmosphere, suggesting a broader envelope that could include CO2, CO, trace O2, and substantial water.

Future work will test predictions on other exoplanets and refine understanding of helium-rich atmospheres, with ongoing research under NASA Hubble Fellow involvement.

Current results are under scrutiny for potential stellar signals, with multi-instrument observations planned to confirm atmospheric presence and composition.

LHS 1140 b has likely retained its atmosphere for over 3 billion years and could persist for about another billion, possibly hosting heavier gases like CO2 or N2.

The planet is roughly 5.6 times Earth's mass and 1.73 times Earth's radius, compatible with an Earthlike composition with a gaseous envelope or possible global ocean.

Experts caution that while atmospheric and water-habitable indicators are promising, direct evidence for life remains unresolved and findings relate to atmosphere and habitability indicators rather than biosignatures.

The team’s model predicted a helium-dominated escaping layer, a hypothesis later supported by observations, implying a detectable atmosphere that could persist with replenishment.