SN 2002bj

SN 2002bj was the explosion of a star in the galaxy NGC 1821, located in the constellation Lepus.[1] The explosion was discovered by Jack Newton in scans of images produced by Tim Puckett. (It was independently discovered by the Lick/Tenagra Observatory as part of their combined supernova search program.) Initially it had an apparent magnitude of about 14.7[2] and was categorized as a Type IIn supernova.[3] However, in 2008 Dovi Poznanski discovered that the spectrum more closely resembled a Type Ia supernova. Further, the energy output was much lower than a typical supernova and the luminosity dropped at a dramatic pace.[4]

SN 2002bj
Other designationsSN 2002bj, AAVSO 0507-15
Event typeSupernova, variable star 
Spectral classSN.IIn 
ConstellationLepus 

A team consisting of Poznanski, Joshua Bloom, Alex Filippenko and others concluded that it was a new category of exploding star. This system is believed to consist of a binary pair of white dwarf stars, with helium being transferred from one dwarf to the other. The accreted helium exploded in a thermonuclear reaction on the surface of the more massive white dwarf, resulting in the observed outburst.[4] In this sense, it was akin to a nova explosion, although the magnitude of the explosion was a thousand times greater.[1] In 2007 Lars Bildsten et al. had predicted this category of explosion would occur in AM Canum Venaticorum star binary systems.[5]

NGC 1821 is an irregular galaxy categorized as type IB(s)m. It is apparent magnitude 14.5 and has a redshift of 0.012029. This galaxy is located about 48 megaparsecs from the Earth.[6]

References
  1. Sanders, Robert. "Rapid supernova could be new class of exploding star". UC Newsroom. University of California, Berkeley. Archived from the original on 2011-06-13. Retrieved 2009-11-06.
  2. Bishop, David (Apr 26, 2002). "Supernova 2002bj in NGC 1821". Astronomy Section, Rochester Academy of Science. Retrieved 2009-11-06.
  3. Matheson, T.; Berlind, P. (March 2002). "Supernova 2002bj in NGC 1821". IAU Circulars. 7844 (5). Bibcode:2002IAUC.7844....5M.
  4. Siegel-Itzkovich, Judy (November 5, 2009). "US-Israeli team's speedily evolving supernova seems to be a new class of exploding star". The Jerusalem Post. Retrieved 2009-11-06.
  5. Bildsten, Lars; Shen, Ken J.; Weinberg, Nevin N.; Nelemans, Gijs (June 2007). "Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries". The Astrophysical Journal. 662 (2): L95–L98. arXiv:astro-ph/0703578. Bibcode:2007ApJ...662L..95B. doi:10.1086/519489.
  6. "NED results for object NGC 1821". NASA/IPAC Extragalactic Database. Retrieved 2009-11-06.
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