The Detonation Mechanism of the Pulsationally Assisted Gravitationally Confined Detonation Model of Type Ia Supernovae

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dc.contributor.author Jordan, G. C. IV
dc.contributor.author Graziani, C.
dc.contributor.author Fisher, R. T.
dc.contributor.author Townsley, D. M.
dc.contributor.author Meakin, C.
dc.contributor.author Weide, K.
dc.contributor.author Reid, L. B.
dc.contributor.author Norris, J.
dc.contributor.author Hudson, R.
dc.contributor.author Lamb, D. Q.
dc.date.accessioned 2018-08-23T19:00:33Z
dc.date.available 2018-08-23T19:00:33Z
dc.date.issued 2012-11-01
dc.identifier.citation Jordan, G., et al. (2012): The Detonation Mechanism of the Pulsationally Assisted Gravitationally Confined Detonation Model of Type Ia Supernovae. The Astrophysical Journal, 759(1). en_US
dc.identifier.uri http://ir.ua.edu/handle/123456789/3752
dc.description.abstract We describe the detonation mechanism composing the “pulsationally assisted” gravitationally confined detonation (GCD) model of Type Ia supernovae. This model is analogous to the previous GCD model reported in Jordan et al.; however, the chosen initial conditions produce a substantively different detonation mechanism, resulting from a larger energy release during the deflagration phase. The resulting final kinetic energy and 56Ni yields conform better to observational values than is the case for the “classical” GCD models. In the present class of models, the ignition of a deflagration phase leads to a rising, burning plume of ash. The ash breaks out of the surface of the white dwarf, flows laterally around the star, and converges on the collision region at the antipodal point from where it broke out. The amount of energy released during the deflagration phase is enough to cause the star to rapidly expand, so that when the ash reaches the antipodal point, the surface density is too low to initiate a detonation. Instead, as the ash flows into the collision region (while mixing with surface fuel), the star reaches its maximally expanded state and then contracts. The stellar contraction acts to increase the density of the star, including the density in the collision region. This both raises the temperature and density of the fuel–ash mixture in the collision region and ultimately leads to thermodynamic conditions that are necessary for the Zel’dovich gradient mechanism to produce a detonation. We demonstrate feasibility of this scenario with three three-dimensional (3D), full star simulations of this model using the FLASH code. We characterized the simulations by the energy released during the deflagration phase, which ranged from 38% to 78% of the white dwarf’s binding energy. We show that the necessary conditions for detonation are achieved in all three of the models. en_US
dc.format.mimetype application/pdf en_US
dc.subject hydrodynamics en_US
dc.subject nuclear reactions, nucleosynthesis, abundances en_US
dc.subject supernovae: general en_US
dc.subject white dwarfs en_US
dc.title The Detonation Mechanism of the Pulsationally Assisted Gravitationally Confined Detonation Model of Type Ia Supernovae en_US
dc.type text en_US


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