A brown dwarf is an object that formed the way stars do, from the
collapse of a molecular cloud, but that,
because it is not massive enough, does not sustain stable
hydrogen fusion in its core.
The first object positively identified as a brown dwarf is
the faint companion to the M1 V (low mass, red, Main Sequence)
star Gliese 229. The brown dwarf is known as
Gliese 229b.
