'It's absolutely exciting!': Astronomers discover an atmosphere around an Earth-like planet in the habitable zone for first time ever - Live Science

What the report says

Live Science reported that astronomers have detected helium escaping from LHS 1140 b, a rocky “super-Earth” about 48 light-years from Earth, offering what researchers describe as the strongest evidence so far that a rocky planet in another star’s habitable zone has retained an atmosphere. The findings were published July 16 in the journal Science. The habitable zone is the orbital region where surface liquid water could be possible, depending on atmospheric conditions.

LHS 1140 b orbits a small, cool red dwarf star and is estimated to have about 5.6 times Earth’s mass. According to Live Science, the research team used the WINERED spectrograph on the Magellan Clay Telescope in Chile to study starlight passing through the planet’s upper atmosphere during a transit. They searched for a specific infrared signal associated with helium and found evidence of gas escaping into space.

A key comparison came in September 2024, when LHS 1140 b and a smaller, closer-in neighboring planet, LHS 1140 c, crossed the star less than 40 minutes apart. Live Science reported that the helium signal appeared for LHS 1140 b but not for LHS 1140 c, even though the inner planet receives more radiation and might be expected to lose gas more visibly if it still had an atmosphere. Researchers interpreted that contrast as evidence that LHS 1140 b has preserved an atmosphere while LHS 1140 c may have lost one.

The result matters because red dwarf stars can erode planetary atmospheres, and many potentially habitable exoplanets orbit such stars. The detection does not show that LHS 1140 b is inhabited or even truly habitable; scientists still do not know the atmosphere’s full composition or whether water is present. Future observations are expected to probe those questions.