Gamma Leonis

Gamma Leonis (γ Leo, γ Leonis) is a binary star system in the constellation Leo. It has the traditional name Algieba or Al Gieba.

Name origin and history

The name Algieba originates from the Arabic الجبهة Al-Jabhah, meaning the forehead. Despite this meaning, the star actually appears in the mane of Leo. The star's Latin name is Juba.

It is known as 軒轅十二 (the Twelfth Star of Xuanyuan) in Chinese. Xuanyuan is the name of Yellow Emperor.

System components

Algieba, as a binary system, consists of two stars. The brighter component has an apparent magnitude of +2.28 and is of spectral class K1-IIIbCN-0.5. The giant K star has a surface temperature of 4,470 K, a luminosity 180 times that of Earth's Sun, and a diameter 23 times that of the Sun. The companion star has an apparent magnitude of +3.51 and belongs to the spectral class G7IIICN-I. The giant G star has a temperature of 4,980 K, a luminosity of 50 times that of the Sun, and a diameter 10 times that of the Sun. With angular separation of just over 4", the two stars are at least 170 AU apart (four times the distance between Pluto and the Sun), and have an orbital period of over 500 years. Because the orbital period is so long, only a fraction of the full path has been observed since discovery.