Scientists spot helium escaping from potentially habitable rocky exoplanet

The planet, known as LHS 1140b, lies about 49 light-years from Earth and orbits a cool red dwarf star. It is about 5.6 times as massive as Earth, 1.73 times larger, and receives roughly 42% of the sunlight that Earth does, placing it within the star's habitable zone where liquid water could potentially exist under the right conditions.

Using the WINERED spectrograph on the Magellan Clay Telescope in Chile, researchers observed helium absorption during a transit of LHS 1140b in September 2024. The signal indicates helium is escaping from the planet's upper atmosphere. Scientists also found signs of helium ahead of the planet in its orbit, suggesting the gas may form a leading tail similar to those previously observed around some gas giant exoplanets.

The researchers concluded that the escaping gas is most likely driven by high-energy radiation from the host star. Their analysis suggests the planet's upper atmosphere is rich in helium but contains very little hydrogen, supporting earlier predictions that lighter hydrogen can gradually escape over time, leaving helium behind.

The team did not detect helium from LHS 1140b during follow-up observations in 2025. They say this does not necessarily mean atmospheric escape stopped, but rather that it may vary over time and could have fallen below the detection limit during those observations.

The researchers also searched for helium around a second rocky planet in the same system, LHS 1140c, but found no evidence of an atmosphere. The result is consistent with previous studies suggesting the smaller, more heavily irradiated planet has little or no atmosphere.

According to the study, the findings improve scientists' understanding of how rocky planets evolve and how some may preserve atmospheres for billions of years, an important factor in assessing their potential habitability.

Earlier, Qazinform News Agency reported on the first detection of sugar in deep space.