2006/11/24 by Tomasz Plewa · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Gamma-ray bursts and supernovae #Neutrino Physics Research #astro-ph
paper · pdf · doi:10.1086/511412
published as Astrophys.J.657:942-960,2007 · ApJ in press; 21 pages, 36 figures at reduced resolution; high resolution version available at http://flash.uchicago.edu/~tomek/Papers/DFD_I_r2.pdf
arxiv created 2006/11/24 · openalex publication_date 2007/03/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions that are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate that the model supernova ejecta are typically composed of about 0.1-0.25 M ☉ of silicon group elements and 0.9-1.2 M ☉ of iron group elements and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg shaped with the axis ratio ≈1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ≈(1.3-1.5) × 10 51 ergs.