23 Feb 2012

Waterworld planet confirmed

5:09 am on 23 February 2012

Astronomers at the Harvard Smithsonian Center for Astrophysics have confirmed the existence of a new class of planet - a waterworld in a solar system outside Earth's.

The exoplanet GJ 1214b, 40 light-years away, is a "Super Earth" - bigger than our planet, but smaller than gas giants such as Jupiter.

It has a thick, steamy atmosphere and observations using the Hubble telescope now seem to confirm that a large fraction of its mass is water.

The BBC reports the The planet was discovered in 2009 orbiting a comparatively cool red-dwarf star at a distance of two million km - meaning temperatures on GJ 1214b probably reach above 200C.

It is about 2.7 times the Earth's diameter.

The study has been accepted for publication by the Astrophysical Journal.