SH2-308 (The Dolphin Head Nebula)

This is an image of IC SH2-308, also known as the Dolphin Head Nebula. It is a huge bubble of mostly ionized oxygen gas about 5,200 light years away in the constellation Canis Major. It is formed by the strong solar winds of a Wolf-Rayet star near the center of the nebula. Wolf-Rayet stars are about 20 times the mass of the sun and are thought to be in the pre-supernova stage of star evolution. The nebula spans an area about the size of the full moon and is about 60 light years in diameter.