So far, only two marginally Earth-like planets have been confirmed as fully matching the criteria for habitability. But the Habitable Exoplanets Catalogue (HEC) has identified more than 15 planets and 30 “exomoons” as potentially habitable.
Future studies with powerful new telescopes will be needed to confirm whether any of these candidates really could harbour life.
Astronomers have established the existence of more than 700 exoplanets and thousands more are awaiting confirmation.
Most are hot gas giants, such as Jupiter and Neptune, orbiting close to their stars.
Only a few of those detected so far have the right size and orbit to be considered suitable for life.
The HEC is being compiled by the Planetary Habitability Laboratory at the University of Puerto Rico in Arecibo, home of the world’s largest single-dish radio telescope.
As well as identifying potentially life-bearing worlds, including “exomoons” such as Pandora in the movie Avatar, it ranks them according to various indices of habitability.