Gliese 229
Gliese 229 (also designated as Gl 229 or GJ 229) is a binary system that has a red dwarf and the first brown dwarf discovered by astronomers. It is located 18.8 light years away in the constellation Lepus. The main star of the binary system has 58% of the mass of the Sun,[1] 69% of the Sun's radius, and a very low projected rotation velocity of 1 km/s at the stellar equator.
The star sometimes randomly gets brighter in luminosity because it is a low activity flare star, which means there is magnetic activity on its surface that causes it to get randomly brighter. It gives off light in the H and K bands due to calcium. It also gives off X-rays from its corona, caused by the interaction between magnetic loops and the gas in its outer atmosphere.[2] There are no large spots on the star that have been detected.[3]
The star is moving through space with a velocity of +12 km/s in the U direction, –11 km/s in the V direction, and –12 km/s in the W direction.[4] Its path around the Milky Way is a little bit squashed, with an eccentricity of 0.07. Its orbit is also tilted just a little bit, with an inclination of 0.005.[3]
References[change | change source]
- ↑ Brandt, Timothy D.; Dupuy, Trent J.; Bowler, Brendan P.; Gagliuffi, Daniella C. Bardalez; Faherty, Jacqueline; Brandt, G. Mirek; Michalik, Daniel (2020). "A Dynamical Mass of 70±5 Jupiter Masses for Gliese 229B, the First Imaged T Dwarf". Astronomical Journal. 160: 4. arXiv:1910.01652. doi:10.3847/1538-3881/abb45e. S2CID 222277091.
- ↑ Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
- ↑ 3.0 3.1 Byrne, P. B.; Doyle, J. G.; Menzies, J. W. (May 1, 1985). "Optical photometry and spectroscopy of the flare star Gliese 229 (=HD42581)". Monthly Notices of the Royal Astronomical Society. 214 (2): 119–130. Bibcode:1985MNRAS.214..119B. doi:10.1093/mnras/214.2.119.
- ↑ Gliese, W. (1969). "Catalogue of Nearby Stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. 22: 1. Bibcode:1969VeARI..22....1G.