We’re beginning to probe the atmospheres of planets other than gas giants, a step forward that the next generation of space- and ground-based instruments will only accelerate. This morning we have word that the habitable zone ‘super-Earth’ eight times as massive as Earth orbiting the star K2-18 has been found to have water vapor in its atmosphere, making it the only exoplanet known to have water as well as temperatures that could sustain that water as a liquid on the surface. This is also our first atmospheric detection of any kind for a planet orbiting in the habitable zone of its star.
Angelos Tsiaras (University College London Centre for Space Exochemistry Data) is lead author on this work, which appears today in Nature Astronomy:
“Finding water in a potentially habitable world other than Earth is incredibly exciting. K2-18b is not ‘Earth 2.0’ as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question: Is the Earth unique?”
Image: UCL’s Angelos Tsiaras. Credit: University College London.
If Dr. Tsiaras’ name seems familiar, it’s because you’re recalling his work on the super-Earth 55 Cancri e, reported in these pages back in 2016 ...