Brown dwarf stars. Artwork of a binary brown dwarf star system. The second brown dwarf star (centre left) is in a mutual orbit around the other brown dwarf star (in the foreground). Brown dwarfs are 'failed stars'. They are more massive than large planets like Jupiter, but are not massive enough to trigger the nuclear reactions that form a star. Brown dwarfs and large planets can be detected by the heat (infrared radiation) they give off, which is generated as they slowly collapse by gravitational contraction. A known example of a binary brown dwarf system is the pair Epsilon Indi Aa and Bb, distant companions of the star Epsilon Indi, around 11.8 light years from Earth.