Editor's Summary

16 March 2006

Magnificent Failures

Brown dwarfs are so-called 'failed stars' that have insufficient mass to sustain nuclear reactions but are too massive to be planets. From this in-between position, brown dwarfs offer unique insights into the nature and origins of both stars and planets. Until now it has not been possible to measure the fundamental physical properties of brown dwarfs directly. But with the discovery of two young brown dwarfs in an eclipsing binary system in the Orion Nebula star-forming region, it has been possible to measure the mass and radius of two in one go. Surprisingly, the less-massive brown dwarf is the hotter of the pair; a finding that runs contrary to the predictions of all current theoretical models of coeval brown dwarfs. This might mean that the two brown dwarfs did not form at the same time, but got together in the recent past.

Letter: Discovery of two young brown dwarfs in an eclipsing binary system

Keivan G. Stassun, Robert D. Mathieu and Jeff A. Valenti

doi:10.1038/nature04570

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