Thor’s Helmet Nebula High Resolution

The nebula has an overall bubble shape, but with complex filamentary structures. The nebula contains several hundred solar masses of ionised material, plus several thousand more of unionised gas. It is largely interstellar material swept up by winds from the central star, although some material does appear to be enriched with the products of fusion and is likely to come directly from the star. The expansion rate of different portions of the nebula varies from 10 km/s to at least 30 km/s, leading to age estimates of 78,500 – 236,000 years. The nebula has been studied at radio and x-ray wavelengths, but it is still unclear whether it was produced at the class O main sequence stage of development, as a red supergiant, luminous blue variable, or mainly as a Wolf-Rayet star.