A failed supernova is an astronomical event in time domain astronomy in which a star suddenly brightens as in the early stage of a supernova, but then does not increase to the massive flux of a supernova. They could be counted as a subcategory of supernova imposters. They have sometimes misleadingly been called unnovae.
Failed supernovae are thought to create stellar black holes by the collapsing of a red supergiant star in the early stages of a supernova. When the star can no longer support itself, the core collapses completely, forming a stellar-mass black hole, and consuming the nascent supernova without having the massive explosion. For a distant observer, the red supergiant star will seem to wink out of existence with little or no flare-up. The observed instances of these disappearances seem to involve supergiant stars with masses above 17 solar masses.
Structure and process
Theoretically, a red supergiant star may be too massive to explode into a supernova, and collapse directly into being a black hole, without the bright flash. They would however generate a burst of gravitational waves. This process would occur in the higher mass red supergiants, explaining the absence of observed supernovae with such progenitors.
List of failed supernovae candidates
09h 50m 55.39s +33° 33′ 14.5″
|Disappearance of a 25-30 MSun F8 supergiant observed in archival HST data|||
|N6946-BH1||March 2009||NGC 6946
20h 35m 27.56s +60° 08′ 08.2″
|Disappearance of a 18-25 MSun red supergiant|||
- Woosley, S. E.; Heger, Alexander (2012). "Long Gamma-Ray Transients from Collapsars". The Astrophysical Journal. 752: 32. arXiv: . Bibcode:2012ApJ...752...32W. doi:10.1088/0004-637X/752/1/32.
- Lee Billings (November 2015). "Gone Without A Bang". Scientific American. 313 (5): 26–27. Bibcode:2015SciAm.313e..26B. doi:10.1038/scientificamerican1115-26b.
- Jon Voisey (2 April 2011). "Finding the Failed Supernovae". Universe Today.
- Colin Robson (20 January 2014). "Failed Supernovae". From Quarks to Quasars.
- Eugene Myers (27 September 2016). "This star was so massive it ate itself before it could go supernova". Astronomy Magazine.
- "Gone without a bang: An archival HST survey for disappearing massive stars". Monthly Notices of the Royal Astronomical Society (published November 2015). 453 (3): 2885–2900. 21 July 2015. arXiv: . Bibcode:2015MNRAS.453.2885R. doi:10.1093/mnras/stv1809.
- Gerke, J. R.; Kochanek, C. S.; Stanek, K. Z. (6 November 2014). "The Search for Failed Supernovae with The Large Binocular Telescope: First Candidates". Monthly Notices of the Royal Astronomical Society (published July 2015). 450 (3): 3289–3305. arXiv: . Bibcode:2015MNRAS.450.3289G. doi:10.1093/mnras/stv776.
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