NGC 2359, also known as "Thor's Helmet", is a Wolf-Rayet ring nebula located in the constellation Canis Major, south of the celestial equator. Unlike most other emission nebulae, this one is not excited by O-stars or white dwarfs, but by a Wolf-Rayet star: HD 56925. This 11.4 magnitude star is located slightly west of the center of the bubble and has an effective temperature of approximately 50,000 ° Celsius. The star builds up enormous radiation pressure, which blows its outer shells into interstellar space. The matter ejected and driven outwards over time forms a bubble, which marks the shock front of the ejecta.Spectral analyses suggest that the bubble-shaped nebula is probably composed of a mixture of material lost by the central Wolf-Rayet star during a previous ejection, and of the surrounding interstellar medium, which is stirred, compressed and ionized by the interaction with its strong stellar wind.
This nebula is out of reach from my location and stands flat just above a row of trees, I obtained test data from DarkMatters. Another reason was to check my workflow with absolutely very good data.
Data:
DarkMatters - Thor Helmet
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