Clear skies reveal water on distant Neptune-sized planet

[dipsydoodle]

A cloud-free atmosphere has allowed scientists to pick out signs of water vapour on a distant planet the size of Neptune: the smallest "exoplanet" ever to reveal its chemical composition.

Previously, only larger, Jupiter-like giants have been studied in this way.

Working with three space telescopes, astronomers deduced the presence of water by measuring the colours of light the planet absorbed when it passed in front of its star.

The find appears in the journal Nature. http://www.nature.com/nature/journal/v513/n7519/full/nature13785.html

http://www.bbc.co.uk/news/science-environment-29343987