Facts about Gacrux
Gacrux is one of the 25 brightest stars in the firmament with an apparent magnitude of 1.59 mag. Furthermore Gacrux with spectral class M3.5 is a red giant and its distance to the Sun is about 90 light-years. Moreover, the star has 1500 times solar luminosity as well as 110 solar diameters. In addition, Gacrux is a binary star with its companion being a 6.4mag bright blue-white star of spectral class A3. Although the companion Gamma Crucis B is with about 400 light-years more than four times as far away as the main star from the sun, it can still be observed with prism binoculars. Moreover, Gacrux is losing mass due to a strong stellar wind and has already evolved from a main sequence B star to a red giant. Therefore today it is already in a phase beyond helium burning.