NGC 2359
Thor’s Helmet
NGC 2359 is an emission nebula located 12,000 lightyears away in Canis Major. It’s also known as Thor’s Helmet, given its similarity in shape to the Norse god’s famous headwear.
The nebula is produced by a massive, hot Wolf-Rayet star emitting a stream of charged particles known as a stellar wind that’s expanding outwards to produce an interstellar bubble.
This bubble is interacting with molecular clouds nearby, causing the ionising of radiation that gives the nebula its glow.
Key Characteristics
Stellar Engine:
The nebula is powered by WR7 (also known as HD 56925), a Wolf-Rayet star that is approximately 280,000 times brighter and 16 times more massive than our Sun. This star is thought to be in a brief pre-supernova stage.
Bubble Structure:
Thor’s Helmet is essentially an interstellar bubble inflated as the star’s solar winds sweep up surrounding gas and dust.
Complex shape:
Unlike a perfect sphere, the nebula has complex “wings” and filamentary structures caused by its interaction with a nearby large molecular cloud.
distinctive Colours:
In long-exposure photography, the nebula often appears blue-green due to the presence of doubly-ionised oxygen atoms, while hydrogen emissions contribute redder hues.
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