by Nancy Atkinson on January 25, 2013
Thor’s Helmet Nebula (NGC 2359) in the constellation of Canis Major. Credit and copyright: Rolf Wahl Olsen.Thor’s Helmet Nebula (NGC 2359) in the constellation  of Canis Major. Credit and copyright: Rolf Wahl Olsen.

At first glance, you might expect this beautiful image to be from a big  ground-based observatory or even one of the space telescopes. But this image was  taken by “amateur” astronomer Rolf Wahl Olsen.  We’ve featured his work before, and he’s  done amazing stuff – such as the first amateur image of another solar system — but even  he says this latest image of an emission nebula might be his best image to date.

It’s a stunning look at what is known as Thor’s Helmet.  This helmet-shaped  feature (complete with wings!) is an emission nebula is located in the  constellation of Canis Major, about 15,000 light years from Earth. The nebula is  a large expanding bubble illuminated by a central star in its last stage of life — a massive Wolf-Rayet star which is shedding its outer layers of gas at an  extremely high rate due to intense radiation pressure. Wolf-Rayet stars are  thought to represent a brief stage of evolution near the end of life for giant  super massive stars; the last unstable phase before the star explodes as a  brilliant supernova. [click  to continue…]


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