Wednesday, September 16, 2009

Rigel is a star in the constellation Orion. With visual magnitude 0.18, it is the sixth brightest star in the sky. Rigel is moving through a region of nebulosity and lights up several dust clouds in its vicinity, the most notable being the IC 2118, which is called the Witch Head Nebula.

Rigel is a contrasting blue supergiant. The theory of stellar structure and evolution shows that Rigel has a mass 18 times that of the Sun. With a dead helium core, it is still in a swelling and cooling phase. It is located at 850 light years away from the Solar System. Rigel should eventually expand to become a red supergiant very much like Betelgeuse.