For the first time, astronomers have found an atmosphere surrounding a rocky, temperate exoplanet that could potentially support life. The planet, LHS 1140b, lies about 50 light years from Earth.
Researchers led by Collin Cherubim at Harvard University made the detection while observing the planet in 2024 at the Las Campanas Observatory in Chile. They identified a spectral line indicating excited helium atoms, which they interpret as gas leaking from the planet's atmosphere.
The finding marks a shift from previous detections, which had only captured atmospheres on large or extremely hot worlds. LHS 1140b orbits in the habitable zone of a small M dwarf star, raising its profile as a candidate for further study.
A follow-up observation in 2025 showed no such helium signature, though Cherubim noted that such variability is not unusual. He plans additional observations to clarify the atmosphere's behavior.
"This planet has now become the best place to search for life outside of our solar system," Cherubim said.