Thursday, February 10, 2011

Who Ate All the Planets? Blame the "Bloatars"

No one has ever seen anything quite like the nine stars spotted by the Hubble Space Telescope in a young cluster called NGC 3603. They are too cool to be ordinary stars, with analysis of their infrared light emissions indicating surface temperatures between 1700 and 2200 kelvin. By this measure, they are more like brown dwarfs, objects intermediate in mass between planets and fully fledged stars. Yet brown dwarfs are dim objects that should be too faint to detect at the cluster's distance from Earth - 20,000 light years.

They think the enigmatic objects are part of stellar systems that spawned planets - then hastily devoured them. Some planets are thought to spiral in towards their stars. That would explain why so many alien worlds have been found in star-hugging orbits. The team says that some may spiral so close that the star "eats" them - the star's gravity rips the planet apart and captures its debris. This captured debris would form a temporary outer atmosphere for the star, which would be cooler than the star's normal light-emitting surface. These bloated stars, or "bloatars", would also be bigger and brighter than brown dwarfs, explaining how they could be seen at such a great distance.

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