NASA’s Hubble Finds Water Vapor on Habitable-Zone Exoplanet for 1st Time

This artist’s impression shows the planet K2-18b, it’s host star and an accompanying planet in this system. K2-18b is now the only super-Earth exoplanet known to host both water and temperatures that could support life. UCL researchers used archive data from 2016 and 2017 captured by the NASA/ESA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b’s atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet’s atmosphere.

If confirmed planet K2-18B will be the only exoplanet known to have both water in its atmosphere and temperatures that could sustain liquid water on a rocky surface.

Recent data from the Hubble Space Telescope have revealed water vapour in the atmosphere of an earth-size planet. The planet called K2-18b, larger in size and surface gravity than that of earth, may also be hostile for potentially radiation environment. For the first time, researchers have detected water vapour signatures in the atmosphere of a planet beyond our solar system that resides in the “habitable zone,” the region around a star in which liquid water could potentially pool on the surface of a rocky planet.

The planet, discovered by NASA’s Kepler Space Telescope in 2015, also has a mass eight times greater than earth’s. That means the surface gravity on this planet would be significantly higher than on our planet. Astronomers at the Center for Space Exochemistry Data at the University College London in the United Kingdom used data from NASA’s Hubble Space Telescope to find water vapour in the atmosphere of K2-18b, an exoplanet around a small red dwarf star about 110 light-years away in the constellation Leo.

If confirmed by further studies, this will be the only exoplanet known to have both water in its atmosphere and temperatures that could sustain liquid water on a rocky surface. Liquid water would only be possible if the planet turns out to be terrestrial in nature, rather than resembling a small version of Neptune.

The high level of activity of its red dwarf star, K2-18b may be more hostile to life as we know it than earth, as it is likely to be exposed to more high-energy radiation.

Image Illustration: M. Kornmesser, ESA/Hubble.