marrow3 -> RE: type 1A supernovae explained.....? (Feb. 26 2010 14:44:32)
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Not that it adds much to what Arash has found out, but this is the abstract to the study. I think that the energy would still be constrained to 2 x the previous limit because each body would have a 1x limit to its mass. Note there are strong caveats to the study so it doesn't settle anything for sure. cheers, Richard Nature 463, 924-925 (18 February 2010) | doi:10.1038/nature08685; Received 24 April 2009; Accepted 16 November 2009 An upper limit on the contribution of accreting white dwarfs to the type Ia supernova rate Marat Gilfanov1,2 & Ákos Bogdán1 1. Max Planck Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany 2. Space Research Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia Correspondence to: Marat Gilfanov1,2 Correspondence and requests for materials should be addressed to M.G. (Email: gilfanov@mpa-garching.mpg.de). Top of page There is wide agreement that type Ia supernovae (used as standard candles for cosmology) are associated with the thermonuclear explosions of white dwarf stars1, 2. The nuclear runaway that leads to the explosion could start in a white dwarf gradually accumulating matter from a companion star until it reaches the Chandrasekhar limit3, or could be triggered by the merger of two white dwarfs in a compact binary system4, 5. The X-ray signatures of these two possible paths are very different. Whereas no strong electromagnetic emission is expected in the merger scenario until shortly before the supernova, the white dwarf accreting material from the normal star becomes a source of copious X-rays for about 10^7 years before the explosion. This offers a means of determining which path dominates. Here we report that the observed X-ray flux from six nearby elliptical galaxies and galaxy bulges is a factor of ~30–50 less than predicted in the accretion scenario, based upon an estimate of the supernova rate from their K-band luminosities. We conclude that no more than about five per cent of type Ia supernovae in early-type galaxies can be produced by white dwarfs in accreting binary systems, unless their progenitors are much younger than the bulk of the stellar population in these galaxies, or explosions of sub-Chandrasekhar white dwarfs make a significant contribution to the supernova rate.
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