Gliese 581d
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Exoplanet near Gliese 581 star 'could host life'

17 May 2011 Last updated at 21:37 BST

A red dwarf star 20 light-years away is providing hints that it hosts the first definitively habitable planet outside our Solar System.

The planet Gliese 581d is at the colder outer edge of the "Goldilocks zone" in which liquid water can be sustained.

Now a study in Astrophysical Journal Letters suggests its atmosphere may keep things warm enough for water.

Kirsty Lang has more details.