Thor’s Helmet Nebula
NGC 2359, or Thor’s Helmet, is located about 15,000 light years away in the constellation Canis Major. It is about 30 light years across.
The central star is a Wolf-Rayet star, a hot, giant star in a pre-supernova stage. It generates a fast stellar wind that has created the nebula as it sweeps through the surrounding molecular cloud.
Image from National Geographic, information from NASA.