On the other side of the range of stars lie the supermassive, superluminous, and very unstable stars. It is believed that all of them are supernova progenitors. While extremely rare, gravitational collapse of star forming clouds can result in the formation of stars with 20-200 solar masses. They live violent and short lives of only a few million years. They burn through their available hydrogen very quickly, with surface temperatures on the order of 30,000 to 200,000K, or about 6 to 35 times that of the sun. Especially towards the end of their short lives, they experience a ‘wind’, which ejects over a billion times the mass of our sun’s wind. This extreme mass loss results in emission lines, and this is how we can detect WR stars.
The most luminous stars discovered reside within the Tarantula nebula in the LMC. While still very bright in the visual spectrum, they produce most of their luminosity in the UV and soft X-rays due to their high surface temperature. Their stellar winds sculpt the surrounding gas and dust, and will likely clear out the star forming material within the nebula in the near future.
The Wolf-Rayet characteristics are thought to exist for all supermassive stars during the later stages of their lives. As a star this massive dies, it will eject all of it’s outer envelope of hydrogen, leaving a massive, superluminous blue core rich in metals. This core is destined to undergo a core collapse supernova. There is nothing that can support a core of this mass against complete collapse, and it will become a singularity of infinite density, or a black hole.
- Shara, M. M.; Faherty, J. K.; Zurek, D.; Moffat, A. F. J.; Gerke, J.; Doyon, R.; Artigau, E.; Drissen, L. (2012). “A Near-Infrared Survey of the Inner Galactic Plane for Wolf-Rayet Stars. Ii. Going Fainter: 71 More New W-R Stars”. The Astronomical Journal 143 (6): 149. arXiv:1106.2196. Bibcode:2012AJ….143..149S. doi:10.1088/0004-6256/143/6/149.
- Sander, A.; Hamann, W. -R.; Todt, H. (2012). “The Galactic WC stars”. Astronomy & Astrophysics 540: A144. arXiv:1201.6354. Bibcode:2012A&A…540A.144S. doi:10.1051/0004-6361/201117830.
