Rigel blue supergiant star. Animation of the location in the night sky and the properties of the B-type star Rigel (Beta Orionis), 860 light years from Earth in the constellation of Orion. Rigel is a blue supergiant star, 78 times the width of the Sun (over 108 million kilometres across) and 21 times the Sun's mass. It is near the end of its life (7 to 9 million years old), and has burnt much of its nuclear fuel. Its mass and hence gravity is high enough that the fusion products that accumulate in its core also begin to fuse, leading to it burning a series of different nuclei in concentric shells of increasing density. This causes them to swell to an enormous size and luminosity. Rigel will eventually explode as a type II supernova. It is spectral type B8, with a luminosity class of Iab. It has a luminosity 120, 000 times that of the Sun, and has an atmospheric temperature of 12, 100 Kelvin. Its spectrum has moderate hydrogen lines and prominent helium lines.