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Brown dwarf stars - Gliese 229 b; BD-211377; HD 42581; HIP 29295; LHS 1827; NSV 2863; SAO 171334; TYC 5945- 765-1 - Space Art Illustration

Gliese 229 b

This is how the brown dwarf Gliese 229 b might appear from a distance of about a half million miles. Glowing like a charcoal ember, Gliese 229 b was discovered in 1995 and is 19 light years from the Earth. This brown dwarf orbits the red dwarf Gliese 229A in the constellation Lepus. (Gliese A can be seen shining dimly on the upper left.) These two dwarfs are about four billion miles apart, about the same distance between Pluto and our sun.

Gliese 229 b is believed to be 30 to 40 times more massive than the planet Jupiter, which is enough mass for Gliese 229 b to sustain deuterium fusion, but not enough to initiate hydrogen fusion like our sun. As a result, Gliese 229 b radiates a temperature of only 1,300 F. It is believed to be two to four billion years old. 

Despite being so much more massive than the planet Jupiter, the diameter of this brown dwarf is believed to be actually slightly less than Jupiter's; Gliese 229 b's greater mass results in its overcoming the internal pressures that sustain Jupiter's greater volume.  


Copyright Walter B. Myers. All rights reserved.

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