Gacrux red giant star. Animation of the location in the night sky and the properties of the M-type star Gacrux (Gamma Crucis), 89 light years from Earth in the constellation of Crux. Gacrux is a red giant star, 84 times the width of the Sun (over 116 million kilometres across) and 1.3 times the Sun's mass. Gacrux was a main sequence star that has evolved into the red giant stage of stellar evolution, a stage that can last tens to hundreds of millions of years. Gacrux is spectral type M3.5, with a luminosity class of III. It has a luminosity 1500 times that of the Sun, and has an atmospheric temperature of 3626 Kelvin. Its spectrum has strong titanium oxide lines and some calcium lines.