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 56Ni 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.
