Brown dwarf
In Astronomy a brown dwarf is an astronomical object that does not have the minimum mass -- eighty times the mass of Planet Jupiter -- required to begin Hydrogen fusion, like traditional stars.[1][2] However, object larger than thirteen times the mass of Jupiter do contain small amounts of the element Lithium, the third lightest element on the Periodic Table. Very small amounts of Lithium were produced during the Big Bang, and the temperature and pressure requirements for Lithium fusion are low enough for Lithium in the core of these objects to fuse.
Brown dwarfs do produce some energy through fusion.[1] But it is so little energy that there outer atmospheres are planet-like, not star like. They are so dim they glow in the infrared.[2]
Teide 1 and Gliese 229 B were the first two brown dwarfs to be discovered, in 1995.[2]
References
[edit | edit source]- ↑ 1.0 1.1
Robert Lea (2017-02-25). "Brown Dwarfs: Failed Stars Resembling Planets". Space.com. Archived from the original on 2026-08-06. Retrieved 2026-08-18.
However, while fully-fledged stars continue to gather material from the gas and dust cloud that births them, brown dwarfs are less successful at this mass harvesting. As a result, they don't reach the masses of the smallest stars and can't trigger the process that defines main sequence stars, like our sun.
- ↑ 2.0 2.1 2.2
Robert M. Hawthorne (2023). "Astronomy and Astrophysics:". EBSCO Research. Archived from the original on 2026-03-15. Retrieved 2026-08-18.
They are called brown dwarfs because, due to their low surface temperature, most of their electromagnetic radiation is in the infrared part of the spectrum; at visible wavelengths, they glow faintly with a dim, dark red color.