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, 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. There are no large spots on the star that have been detected.

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. 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.

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Category:Binary stars