Thursday, December 01, 2005
Planets of a Brown Dwarf
The Spitzer Space Telescope has found a dust disk orbiting a brown dwarf. The BD is about eight times the mass of Jupiter, and about half the size of the largest discovered planet.
Brown dwarfs are celestial bodies (sidus, in Latin) that lacked the necessary mass to ignite into a star. They've been heated by gravity and are far cooler than red stars. But they can be detected in the infrared by the afterglow of their formation.
Because of the scattering of energy, we can detect diffuse disks of dust much more easily than planets. In fact, disks were spotted around stars years before we detected the first planets.
Giant planets in our own solar system have bevies of moons, so this finding isn't really surprising. But it does confirm the suspicion that planets are very, very common in our galaxy, even around bodies that failed as stars.
