Beyond the Bubble Catastrophe of Type Ia Supernovae: Pulsating Reverse Detonation Models

We describe a mechanism by which a failed deflagration of a Chandrasekhar-mass carbon-oxygen white dwarf can turn into a successful thermonuclear supernova explosion, without invoking an ad hoc high-density deflagration-detonation transition. Following a pulsating phase, an accretion shock develops above a core of ~1 M☉ composed of carbon and oxygen, inducing a converging detonation. A three-dimensional simulation of the explosion produced a kinetic energy of 1.05 × 1051 ergs and 0.70 M☉ of 56Ni, ejecting scarcely 0.01 M☉ of C-O moving at low velocities. The mechanism works under quite general conditions and is flexible enough to account for the diversity of normal Type Ia supernovae. In given conditions the detonation might not occur, which would reflect in peculiar signatures in the gamma-ray and UV wavelengths.