Brown Dwarfs

Relative sizes of a Brown Dwarf relative to other bodies

Astronomers have found many types of objects in orbit around stars and as free-floating objects. These range from other full-sized stars like our sun (binary star systems) to Jupiter sized planets (never directly imaged but inferred from radial-velocity spectroscopy). The relative sizes of these various types of bodies are shown above for comparison. Even though a brown dwarf can be similar in diameter to a Jupiter sized planet, brown dwarfs are 13-75 times more massive and they can appear on the order of 100-1,000,000 times brighter than a Jupiter sized planet at infrared wavelengths where they are studied with telescopes.

Infrared spectra of Brown Dwarfs often reveal gases such as water vapor, methane, other transient species and give clues to the initial mass function of the cloud in which they formed.