Updated

Updated · spacedaily.com · Aug 6

Astronomers Confirm Atmosphere on LHS 1140b, a Rocky Exoplanet 49 Light-Years Away

Updated

Updated · spacedaily.com · Aug 6

Astronomers Confirm Atmosphere on LHS 1140b, a Rocky Exoplanet 49 Light-Years Away

Q: What heavier, potentially life-supporting gases might be hiding beneath the escaping helium layer of this tidally locked alien world?

The most likely heavier gases scientists think could sit beneath LHS 1140b’s escaping helium are water vapor and carbon dioxide, with oxygen and other molecules also possible but unconfirmed. The helium detection only probes the planet’s upper atmosphere, where light gases are easiest to spot as they leak into space. Researchers say that does not mean the whole atmosphere is made only of helium. Instead, current models suggest LHS 1140b may have a layered atmosphere: helium-rich and hydrogen-poor high above, with heavier gases lower down, closer to the surface where habitability would matter most. Among the strongest candidates are water vapor, because the planet lies in the habitable zone and may be warm enough for liquid water, and carbon dioxide, because it could help create a greenhouse effect that stabilizes surface temperatures. Scientists also want to search for oxygen and other molecules that could reveal the planet’s climate and chemistry. Farther in the future, they hope to look for chemical imbalances that might hint at biological activity, including photosynthesis-related gases. For now, none of those heavier gases has been detected. The helium signal is being treated as evidence that an atmosphere likely exists, not proof yet of a life-supporting one. Follow-up observations with JWST, Hubble and ground-based telescopes are expected to test whether water, carbon dioxide, oxygen or other molecules are actually present beneath the escaping helium layer.

3 articles · Updated · spacedaily.com · Aug 6

Data published in Science on July 16 indicates LHS 1140b has an atmosphere, giving the Earthlike exoplanet all three traits scientists see as key for life: rock, air and potentially liquid water.
Helium escaping from the planet revealed that atmosphere, while its mass—about 6 times Earth’s—and radius—1.7 times Earth’s—suggest it is likely still rocky rather than a gas-dominated world.
LHS 1140b sits in its star’s habitable zone 49 light-years from Earth, orbiting a cool red dwarf every 25 days at about 8.8 million miles and likely remaining tidally locked.
Researchers now plan follow-up studies over the next few years to test for a greenhouse effect before pursuing more ambitious searches for water, oxygen and other possible biosignature molecules.