Gliese 229

The Gliese 229 stellar system consists of a red dwarf star, orbited by a pair of closely bound brown dwarfs. The system is located about 19 lightyears from the Solar system.^[1]

The brown dwarfs are found about 250 astronomical units from their primary, and take 250 years to complete their orbit.^[2] The brown dwarfs are about two percent of an astronomical unit from one another -- about 16 times the distance between Planet Earth and Luna, our moon. They take 12 days to orbit one another.

References

↑ Robert M. Hawthorne (2023). "Astronomy and Astrophysics:". EBSCO Research. Archived from the original on 2026-03-15. Retrieved 2026-08-18. The first bodies to be identified as brown dwarfs were Teide 1 in the Pleiades and Gliese 229B, part of a binary star system with the true star Gliese 229, located in the constellation Lepus (the Hare). Since Gliese 229’s distance from the Earth was known, the brown dwarf’s distance was also known: about 19 light-years.
↑ "First Brown Dwarf Discovered is Actually Twins". American Museum of Natural History. 2024-10-15. Archived from the original on 2025-10-03. Retrieved 2026-08-17. Using two specialized instruments at the European Southern Observatory’s Very Large Telescope in Chile, the researchers found that Gliese 229B is a pair of tight-knit brown dwarfs, weighing about 38 and 34 times the mass of Jupiter. Now called Gliese 229Ba and Gliese 229Bb, the brown dwarfs are extremely close to each other, astronomically speaking—just 16 times larger than the distance between Earth and the Moon. The pair race around each other every 12 days and orbit their star every 250 years.

[Ebsco-BrownDwarfs-2023-1] Robert M. Hawthorne (2023). "Astronomy and Astrophysics:". EBSCO Research. Archived from the original on 2026-03-15. Retrieved 2026-08-18. The first bodies to be identified as brown dwarfs were Teide 1 in the Pleiades and Gliese 229B, part of a binary star system with the true star Gliese 229, located in the constellation Lepus (the Hare). Since Gliese 229’s distance from the Earth was known, the brown dwarf’s distance was also known: about 19 light-years.

[amnh-Gliese229B-2024-10-15-2] "First Brown Dwarf Discovered is Actually Twins". American Museum of Natural History. 2024-10-15. Archived from the original on 2025-10-03. Retrieved 2026-08-17. Using two specialized instruments at the European Southern Observatory’s Very Large Telescope in Chile, the researchers found that Gliese 229B is a pair of tight-knit brown dwarfs, weighing about 38 and 34 times the mass of Jupiter. Now called Gliese 229Ba and Gliese 229Bb, the brown dwarfs are extremely close to each other, astronomically speaking—just 16 times larger than the distance between Earth and the Moon. The pair race around each other every 12 days and orbit their star every 250 years.

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