The first "ocean planet" ? Gliese 1214 b could be the first of this new category of exoplanets. And for good reason : Japanese researchers confirm the presence of water in its atmosphere.
Discovered on December 2009 thanks to MEarth Project, Gliese 1214 b is a super-earth located at 42 light-years from the Sun. It orbits at only 2.1 million km of its star, GJ 1214, a red dwarf, and does a full tour in about 40 hours. Its mass is about 6 or 7 times Earth's and its radius is 17,000 km (2.6 times Earth's radius).
To confirm the presence of water, astronomers installed a blue filter on Subaru Telescope to measure Rayleigh scattering. Gliese 1214 b presented a low scattering, proving the presence of water. However the atmosphere of the exoplanet could be very cloudy, the next observations will give us more about it.
An other proof that Gliese 1214 b has water : its density is 1.8 (so very low). So the planet has got probably 75 % of water (or ice water) and 25 % of rock and metal (for the core with a 4,000 km radius).
However, because the planet is very close to its star, it's temperature is about 200°C, so it couldn't welcome life.
Source : Maxisciences (FR)