Astronomers have discovered a fascinating Earth-like exoplanet called Gliese 12 b, located 40 light-years away. This potentially habitable planet orbits its star every 12.8 days and is similar in size to Venus, slightly smaller than Earth. Its estimated surface temperature is 42°C (107°F) without an atmosphere, cooler than most of the 5,000 confirmed exoplanets.
Habitability and Atmospheric Conditions
Determining whether Gliese 12 b has an atmosphere is crucial for assessing its habitability. Its atmosphere could resemble Earth’s, or be more akin to Venus’ runaway greenhouse effect, or it could be something entirely different. Understanding the planet’s atmosphere will provide insights into why Earth and Venus evolved differently and whether Gliese 12 b can sustain liquid water and potentially support life.
Comparison with other known Exo Planets
NASA considers Gliese 12 b one of the few exoplanets worthy of further study. It is the closest, transiting, temperate, Earth-sized world discovered to date and a potential target for the James Webb Space Telescope. Unlike Proxima Centauri b, another nearby Earth-like exoplanet that does not transit its star, Gliese 12 b can be studied using the transit method, which measures the dip in the star’s brightness as the planet passes in front of it, providing chemical clues about its atmosphere.
Observations
The discovery was published in the Monthly Notices of the Royal Astronomical Society by two international teams. Gliese 12 b orbits a cool red dwarf star, Gliese 12, which is about 27% the size of our Sun and 60% as hot. The planet receives 1.6 times more energy from its star than Earth does from the Sun, and about 85% of what Venus receives, making its surface temperature highly dependent on atmospheric conditions.
Researchers aim to determine if planets like Gliese 12 b, orbiting cool stars, can retain their atmospheres, advancing our understanding of planetary habitability. The star’s relative calmness, with no signs of extreme magnetic activity, raises hopes that Gliese 12 b’s atmosphere may remain intact. This discovery adds to the small but growing list of temperate, Earth-like exoplanets close enough for detailed atmospheric studies, such as those in the TRAPPIST-1 system, though most of those planets lack atmospheres.
