Astronomers have made a significant breakthrough: they’ve detected evidence of an atmosphere around a rocky exoplanet located in the habitable zone of its star. The planet in question is LHS 1140b, which orbits a red dwarf about 48 light-years from Earth.
Using an infrared spectrograph at the Magellan Clay Telescope in Chile, researchers observed helium escaping from the upper atmosphere of LHS 1140b. This leakage, driven by high-energy radiation (X-rays and extreme ultraviolet) from the host star, provided the key signature.
The discovery is notable because LHS 1140b is a «super-Earth» (its mass is about 5.6 times that of Earth, and its radius is 1.73 times Earth’s), yet it retains a gas envelope. In contrast, a nearby planet in the same system (LHS 1140c), which receives significantly more stellar radiation, shows no signs of an atmosphere. This suggests that stellar irradiation plays a crucial role in atmospheric retention.
The presence of escaping helium implies that there might be heavier elements (like water, carbon, nitrogen, and oxygen) in lower layers of the atmosphere. This is a promising sign for the search for life-supporting environments beyond Earth. Future observations with telescopes like James Webb and Hubble will aim to detect other molecules (e.g., H₂O, CO₂) to test whether LHS 1140b has a stable, long-lived atmosphere.
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