Brown dwarfs
A brown dwarf is a substellar object that falls between the most massive planets and the least massive stars. Brown dwarfs have a mass of approximately 13 to 80 times that of Jupiter, too small to sustain hydrogen fusion in their cores but massive enough to emit heat and light from deuterium fusion. They matter because they fill a crucial gap in our understanding of how objects form and evolve in the universe. The coolest brown dwarfs were not discovered until 1994, and since then, thousands have been identified using infrared detection. Because brown dwarfs emit most of their light in the infrared and are relatively dim, they help astronomers study the processes of stellar and planetary formation across a wider range of masses than stars alone would allow.
Sources
- en.wikipedia.org: “Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars.”
- en.wikipedia.org: “Their mass is approximately 13 to 80 times that of Jupiter (MJ)—not big enough to sustain nuclear fusion of hydrogen into helium in their cores, but massive enough to emit some light and heat from deuterium fusion”
- en.wikipedia.org: “it was not until 1994 that the first unambiguous brown dwarfs were discovered”