Algieba (Gamma Leonis)


Algieba (Gamma Leonis). Photo credit: Rainer Anton.

Algieba (Gamma Leonis) is the third brightest star in the constellation Leo. Algieba is a magnificent binary system with orange-red and yellow components visible through a modest telescope under good atmospheric conditions; its Arabic name means "the forehead". The brighter component (magnitude 2.6) is a giant K star with a surface temperature of 4,400 K and a luminosity of 180 times that of the Sun; its partner is a magnitude 3.8 giant G star with a temperature of 4,900 K and a luminosity of 50 times that of the Sun. The angular separation of just over 4 arcseconds means that the two stars are at least 170 astronomical units apart – four times the Pluto-Sun distance – and have an orbital period of over 500 years.


visual magnitude 2.01
absolute magnitude -0.92
spectral type K0III + G7III
distance 126 light-years (39 pc)
position RA 10h 19m 58.3s,
Dec +19° 50' 30"
other designations 41 Leo, BD +20°2467, HD 89484,
LTT 12764/12765, GCTP 2423.00,
SAO 81298, ADS 7724, HIP 50583