GAT: brown dwarf - eMyTextBooks

GAT: brown dwarf

A brown dwarf is an astronomical object that has insufficient mass to allow its internal gravity to compress and heat the hydrogen in its core to fusion point.

A brown dwarf has a mass between 13 and 75-80 Jovian masses. Anything more massive would be a star; anything less massive a Jovian-type planet.

Brown drawfs are not really brown: they glow mostly in the infrared, with some newer-created brown drawfs glowing red, from 1500 to 2000 Kelvins. The phrase came into being only as a way to distinguish brown drawfs from red dwarfs and black dwarfs.

One feature that distinguishes a brown dwarf from a star is the presence of methane (CH4) in its compositon. Stars make carbon as part of the fusion process, but the carbon in stars usually combines with oxygen to form carbon monoxide (CO).

Several brown drawfs have been discovered, usually in orbit around main sequence stars.