A Wolf-Rayet star is a rare, massive, and extremely hot star characterized by strong stellar winds and significant mass loss. These stars are in a late stage of stellar evolution, often preceding a supernova explosion, and are known for their broad emission lines of ionized elements in their spectra.
Source: science.nasa.gov
09/06/2026

Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the cosmic head-covering is more like an interstellar bubble, blown by a fast wind from the bright, massive star near the bubble's center. 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. NGC 2359 is located about 15,000 light-years away toward the constellation of the Great Overdog. This sharp image is a combination of deep images taken in light emitted by hydrogen (red) and oxygen (blue). The star in the center of Thor's Helmet is expected to explode in a spectacular supernova sometime within the next few thousand years. Sky Surprise: What picture did APOD feature on your birthday? (after 1995)