Atmosphere detected on Earth-like planet in habitable zone

Astronomers have detected an atmosphere on a rocky exoplanet located in the habitable zone of its star, marking the first time such a feature has been confirmed on a world similar in size and composition to Earth. The planet, designated GJ 1132b, orbits a red dwarf star about 39 light-years away in the constellation Vela. This discovery is significant because it demonstrates that Earth-like planets in the temperate region around their stars can retain gaseous envelopes, a key ingredient for potential habitability.

The finding was made using observations from the Hubble Space Telescope and the Spitzer Space Telescope. The team, led by researchers at the University of Cambridge, analyzed the planet's transit — the slight dimming of starlight as the planet passes in front of its star — and identified signatures of water vapor and possibly methane in the planet's atmosphere. The planet itself is about 1.4 times the size of Earth and has a mass roughly 1.6 times that of our planet, placing it firmly in the rocky category.

This discovery matters because it provides the first concrete evidence that a rocky planet in the habitable zone can have an atmosphere, a crucial step toward understanding whether such worlds could support life. Previously, astronomers had found atmospheres only on gas giants or on planets too hot to be considered habitable. GJ 1132b receives about 19 times more radiation from its star than Earth does from the Sun, but its atmosphere appears to be thick enough to potentially regulate surface temperatures.

The research was published in the Astronomical Journal. The team plans to use the upcoming James Webb Space Telescope to study the planet's atmosphere in more detail, searching for additional molecules such as oxygen or carbon dioxide that could indicate biological activity. While GJ 1132b itself is likely too hot for life as we know it, the discovery paves the way for studying similar planets that may be more temperate.