The problem is that a planet that close should be consumed by its parent star in less than a million years, say the authors at Keele University in Britain. The star Wasp-18 is believed to be about a billion years old, and because stars and the planets around them are thought to form at the same time, Wasp-18b should have been reduced to cinders ages ago.
"This planet should spiral inwards on such a short time scale that the likelihood of seeing it is very low," said Coel Hellier, an astrophysicist at Keele.
"That's a paradox," said Douglas P. Hamilton, an astronomer at the University of Maryland who wrote a commentary accompanying the report. He said there were a variety of possible explanations, none of them very satisfactory.
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