D. M. Townsley et al. 2007 ApJ 668 1118 doi:10.1086/521013
D. M. Townsley1,2, A. C. Calder1,3,4, S. M. Asida5, I. R. Seitenzahl2,6, F. Peng1,2,3,7, N. Vladimirova3, D. Q. Lamb1,3,6, and J. W. Truran1,2,3,6,8
Show affiliationsWe develop an improved method for tracking the nuclear flame during the deflagration phase of a Type Ia supernova and apply it in a study of the variation in outcomes expected from the gravitationally confined detonation (GCD) paradigm. A simplified three-stage burning model and a nonstatic ash state are integrated with an artificially thickened advection-diffusion-reaction (ADR) flame front in order to provide an accurate but highly efficient representation of the energy release and electron capture in and after the unresolvable flame. We demonstrate that neither our ADR nor our energy release methods generate significant acoustic noise, as has been a problem with previous ADR-based schemes. We proceed to model aspects of the deflagration, particularly the role of buoyancy of the hot ash, and find that our methods are reasonably well behaved with respect to numerical resolution. We show that if a detonation occurs in material swept up by the material ejected by the first rising bubble but gravitationally confined to the white dwarf (WD) surface (the GCD paradigm), the density structure of the WD at detonation is systematically correlated with the distance of the deflagration ignition point from the center of the star. Coupled to a suitably stochastic ignition process, this correlation may provide a plausible explanation for the variety of nickel masses seen in Type Ia supernovae.
hydrodynamics; nuclear reactions, nucleosynthesis, abundances; supernovae: general; white dwarfs
Issue 2 (2007 October 20)
Received 2007 March 13, accepted for publication 2007 June 7
D. M. Townsley et al. 2007 ApJ 668 1118
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