AT BETWEEN 10 and 100 times the size of the Sun, you might think red giants
are impervious to all but the most cataclysmic cosmic events. But according to
astronomers in Israel and the US, those at the heart of dense star clusters may
be swallowing wandering planets鈥攁nd it鈥檚 turning them blue.
When a red giant swallows a planet, it makes the giant spin faster and shed
its outer layers into space. 鈥淭he more mass a red giant loses, the bluer it
becomes,鈥� explains Noam Soker of the University of Haifa.
Soker and his team based their conclusion on recent estimates that globular
star clusters may contain more than 100,000 free-floating planets in each cubic
light year, meaning up to 10 per cent of red giants may swallow such a planet at
some point in their lifetime.
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