Brown Dwarf Stars

Low mass stellar objects (< 0.08 solar mass) do not generate enough heat from gravitational compression to initiate hydrogen burning. Deuterium fusion does occur. These "stars" are the brown dwarfs.

With small size and cool temperatures (< 1000K,) brown dwarfs have a very low luminosity and even the closest are very faint.

They have been recently confirmed with images and spectra, and are found to have Li (6708Å), bands of methane (CH4), and a lack of features found in M and L stars (TiO, Vo, ZrO, FeH, CrH, etc).

Examples include Gliese229B, Teide 1, PPL1.

Gliese229 and bona-fide brown dwarf Gliese229B!

Credit: T. Nakajima and S. Kulkarni (Caltech), S. Durrance and D.Golimowski (JHU), STScI, and NASA
November, 1995

Brown Dwarf