NGC 2359, better known as the Thor's Helmet nebula, is actually more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble's center sweeps through a surrounding molecular cloud. The central star is an extremely hot giant Wolf-Rayet star, thought to be in a brief, pre-supernova stage of evolution. It lies about 15,000 light years from Earth in the constellation Canis Major, measuring about 30 light years.
It is one of the best known Wolf-Rayet nebular structures, along with NGC 6888, and the name Thor's Helmet is due to its remarkable resemblance to depictions of the headwear donned by the famed Norse god of thunder. This INT image captures striking details of the nebula's filamentary structures. The bluish colour remarks the strong emission due to oxygen atoms in the glowing gas. In fact, it can be visually seen with telescopes of moderate aperture using an [OIII] narrow-band filter.
Javier Méndez (Public Relations Officer)
The Isaac Newton Group of Telescopes
Labels: NGC 2359