Three‐Dimensional Simulations of the Deflagration Phase of the Gravitationally Confined Detonation Model of Type Ia Supernovae

Abstract

We report the results of a series of three-dimensional (3D) simulations of the deflagration phase of the gravitationally confined detonation mechanism for Type Ia supernovae. In this mechanism, ignition occurs at one or several off-center points, resulting in a burning bubble of hot ash that rises rapidly, breaks through the surface of the star, and collides at a point opposite the breakout on the stellar surface. We find that detonation conditions are robustly reached in our 3D simulations for a range of initial conditions and resolutions. Detonation conditions are achieved as the result of an inwardly directed jet that is produced by the compression of unburnt surface material when the surface flow collides with itself. A high-velocity outwardly directed jet is also produced. The initial conditions explored in this paper lead to conditions at detonation that can be expected to produce large amounts of 56 Ni and small amounts of intermediate-mass elements. These particular simulations are therefore relevant only to high-luminosity Type Ia supernovae. Recent observations of Type Ia supernovae imply a compositional structure that is qualitatively consistent with that expected from these simulations.

Three-dimensional simulations of gravitationally confined detonations compared to observations of SN 1991T

“…Since the spatial scales relevant to the initiation of a detonation cannot be resolved in full-star multi-dimensional explosion simulations (see the discussion in Seitenzahl et al 2009a), it is common practice (e.g. Jordan et al 2008Jordan et al , 2012aGuillochon et al 2010;Pakmor et al 2011Pakmor et al , 2012b to pick a certain critical density ρ crit and temperature T crit that a cell composed of nuclear fuel must exceed for a detonation to be initiated. However, these critical values are no more than informed guesses based on separate high-resolution onedimensional detonation initiation calculations (e.g.…”

Gravitational Wave Emission from the Single-Degenerate Channel of Type Ia Supernovae

“…Both the deflagration-to-detonation transition (DDT) [7] and the gravitationally-confined detonation (GCD) [8,9] models for the SN Ia explosion mechanism begin with this stage of off-centered ignition. The predictions of the two mechanisms depart by the evolution of the bubble as it approaches breakout.…”

“…If the detonation is sufficiently asymmetric, this GW signal may be detectable by proposed third-generation GW instruments. We next develop a more refined estimate by post-processing three-dimensional (3D) simulations of the GCD mechanism [9].…”

“…Methodology.-We simulate the evolution of a 3D hydrodynamical GCD SNe Ia in the SD channel [9]. The progenitor WD is evolved from the onset of deflagration through detonation.…”

Detailed Spectral Modeling of a Three‐dimensional Pulsating Reverse Detonation Model: Too Much Nickel

“…The alternative is a delayed detonation ( Khokhlov 1991a( Khokhlov ,1991b( Khokhlov , 1991c( Khokhlov , 1993Gamezo et al 2005;Mazzali et al 2007) where the deflagration accelerates into a detonation or some other process that turns the deflagration into a detonation. Two alternatives that act in a manner similar to the delayed-detonation scenario are the ''gravitationally confined detonation'' (Plewa et al 2004;Jordan et al 2007) and the ''pulsating reverse detonation'' (Bravo & García-Senz 2006).…”