Astronomers find a planet denser than lead
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This planet is challenging to models. How did it form? It most likely formed farther out from the star — gravitational influences make it hard for a large planet to form close to a star — and then gradually moved in.
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It was discovered by COROT, an orbiting European Space Agency mission designed to look for stars that dip in brightness as an orbiting planet passes in front of them. That gives the size of the planet (the amount the light dims is proportional to the size of the planet).
As a planet (the alternative is classifying it as a brown dwarf – a failed star, not a planet), COROT-exo-3b would be the densest known planet.
Related: COROT discovery stirs exoplanet classification rethink – Planet, Less Dense Than Cork, Is Discovered – Hot Ice Planet – Physics May Need a Revision



