Stellar 'Pollution' May Be Remains Of Watery Planets

Sucking up rocky pollutants (Image: NASA/JPL-Caltech)

From New Scientist:

A lost generation of planets may now be no more than a whiff of pollution in the atmospheres of their dead parent stars. If so, it would suggest that rocky planets are common, and hints that most such planets have water.

White dwarfs – the dense remnants of ordinary stars – usually have very pure atmospheres dominated by the lightweight elements hydrogen and helium, because heavier elements tend to sink into a star's interior. But about 20 per cent of white dwarfs are tainted by traces of heavier elements.

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