page_title: Brown dwarf
section_title: Low-mass brown dwarfs versus high-mass planets
hierarchical_section_title: Brown dwarf / Theory / Low-mass brown dwarfs versus high-mass planets
caption_attribution_description: English: Brown dwarf HD 29587 B.
context_page_description: A brown dwarf is a type of substellar object that has a mass between those of the heaviest gas giant planets and the least massive stars, i.e. about 13 to 75–80 times that of Jupiter, or about 2.5×10²⁸ kg to 1.5×10²⁹ kg. Below this range are the sub-brown dwarfs, and above it are the red dwarfs. Brown dwarfs may be fully convective, with no layers or chemical differentiation by depth.
  Unlike the stars in the main sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen to helium in their cores. They are, however, thought to fuse deuterium. If their mass is > 65 MJ they may also fuse lithium. It is also debated whether brown dwarfs would be better defined by their formation processes rather than by their nuclear fusion reactions.
  Stars are categorized by spectral class, with brown dwarfs designated as types M, L, T, and Y. Despite their name, brown dwarfs are of different colors. Many brown dwarfs would likely appear magenta to the human eye, or possibly orange/red. Brown dwarfs are not very luminous at visible wavelengths.
  There are planets known to orbit brown dwarfs, such as 2M1207b, MOA-2007-BLG-192Lb, and 2MASS J044144b.
context_section_description: Like stars, brown dwarfs form independently, but, unlike stars, lack sufficient mass to "ignite". Like all stars, they can occur singly or in close proximity to other stars. Some orbit stars and can, like planets, have eccentric orbits.
caption: An artistic concept of the brown dwarf around the star HD 29587, a companion known as HD 29587 b, and estimated to be about 55 Jupiter masses.
exif: {}