GACRUX - is the third brightest star in constellation Crux (the Southern Cross) and one of the brightest stars in the nighttime sky.Since Gamma Crucis is at roughly −60° declination, it is only visible south of the Tropic of Cancer and therefore didn't receive an ancient traditional name. Gamma Crucis is a binary star, 88 light years distant from Earth. The main star possesses an apparent magnitude of +1.6. The color of Gamma Crucis is bright red.
This star has evolved out of the main sequence to become a red giant star, and may be passing out of the Helium-burning stage. It is also semi-variable with a period of about 90 days. The atmosphere is contaminated with barium, which are likely due to neutron emission from a companion that has since become an unseen white dwarf.
