Wolf-Rayet stars are amongst the most massive stars known. The surface temperature level of the staying star can be over 200,000 K, making them the most luminescent stars known. Even with the outer layers of a Wolf-Rayet star cast off, the central star is still much more massive than the Sun. We can see the spectra of elements within a supernova, and we d never ever seen a spectrum that matched a Wolf-Rayet star. Because this supernova was recognized by spectra of the surrounding nebula, it isnt clear whether the explosion was an easy supernova, or whether it was a more intricate hybrid procedure where the upper layer of the star took off while the core collapsed directly to a black hole.
We frequently think about supernova explosions as inescapable for big stars. Huge star runs out of fuel, gravity collapses its core and BOOM! But astronomers have actually long believed at least one type of big star didnt end with a supernova. Referred to as Wolf-Rayet stars, they were thought to end with a quiet collapse of their core into a black hole. However a brand-new discovery discovers they might end up being supernovae after all.
Wolf-Rayet stars are amongst the most massive stars known. They are at completion of their brief lives, however instead of just running out of fuel and blowing up, they press out their outer layers with an extremely powerful excellent wind. This produces a surrounding nebula abundant in ionized helium, carbon, and nitrogen, but practically no hydrogen. The surface temperature level of the staying star can be over 200,000 K, making them the most luminescent stars understood. Since many of that light is in the ultraviolet range, they are not especially brilliant to the naked eye.
In a big star, various elements are in layers prior to the star takes off. Credit: Itai Raveh
Even with the outer layers of a Wolf-Rayet star cast off, the central star is still much more huge than the Sun. We can see the spectra of components within a supernova, and we d never ever seen a spectrum that matched a Wolf-Rayet star. As our discovery of supernovae became prevalent, some astronomers started to wonder if Wolf-Rayet stars had a peaceful death rather.
This newest study reveals that at least some Wolf-Rayet stars do end up being supernovae. Instead, they were part of a nebula broadening away from the star at more than 1,500 km/s.
A spectra from SN 2019hgp. Credit: Itai Raveh
In other words, prior to the supernova occurred, the progenitor star was surrounded by a nebula abundant in neon, carbon, and nitrogen, while lacking the lighter aspects of hydrogen and helium. This matches the structure of a Wolf-Rayet star exceptionally well.
Since this supernova was determined by spectra of the surrounding nebula, it isnt clear whether the explosion was a basic supernova, or whether it was a more complicated hybrid process where the upper layer of the star exploded while the core collapsed directly to a black hole. It will take more observations to identify the information. Whats clear is that a minimum of some Wolf-Rayet stars do not go quietly into the night.
Referral: Gal-Yam, A., et al. “A WC/WO star blowing up within a broadening carbon– oxygen– neon nebula.” Nature 601.7892 (2022 ): 201-204.
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