ABSTRACT. 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.

Subject headings: hydrodynamics; nuclear reactions, nucleosynthesis, abundances; supernovae: general; ultraviolet: stars

Print publication: Issue 2 (2006 May 10)
Received 3 January 2006, accepted for publication 30 March 2006
Published 26 April 2006