Astronomy Picture of the Day
    


Thor s Helmet (NGC 2359) and Planetary Nebula
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Thor s Helmet (NGC 2359) and Planetary Nebula
Credit & Copyright: Rogelio Bernal Andreo, Ray Gralak
Explanation: At the right, Thor's Helmet (NGC 2359) seems to gaze across a lovely star field. The broad skyscape itself covers about 1.5 degrees or 3 full moons toward the constellation Canis Major. A close look at the lower left corner of the image might identify the object of the cosmic stare as a faint, round nebula. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. The helmet 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. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre- supernova stage of evolution. In contrast, the faint, round nebula is a planetary nebula, the gaseous shroud of a dying lower mass star. The distance to Thor's Helmet is estimated to be about 15,000 light-years.


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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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Based on Astronomy Picture Of the Day

Publications with keywords: NGC 2359 - planetary nebula - Wolf-Rayet star
Publications with words: NGC 2359 - planetary nebula - Wolf-Rayet star
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