Gliese 229B Light Spectrum

A substellar companion was discovered in 1994 by Caltech astronomers Kulkarni, Tadashi Nakajima, Keith Matthews, and Rebecca Oppenheimer, and Johns Hopkins scientists Sam Durrance and David Golimowski. It was confirmed in 1995 as Gliese 229B, one of the first two instances of clear evidence for a brown dwarf, along with Teide 1. Although too small to sustain hydrogen-burning nuclear fusion as in a main sequence star, with a mass of 21 to 52. 4 times that of Jupiter (0. 02 to 0. 05 solar masses), it is still too massive to be a planet. As a brown dwarf, its core temperature is high enough to initiate the fusion of deuterium with a proton to form helium-3, but it is thought that it used up all its deuterium fuel long ago. This object now has a surface temperature of 950 K.