Surface and Core Detonations in Rotating White Dwarfs

Abstract

The feasibility of the Double Detonation mechanism, -a surface Helium-detonation followed by the complete carbon detonation of the core-, in a rotating white dwarf with a mass $\simeq 1 M_{\odot}$ is studied using three-dimensional hydrodynamic simulations. Assuming rigid rotation, the rotational speed is taken high enough as to considerably distort the initial spherical geometry of the white dwarf. Unlike spherically symmetric models, we found that when helium ignition is located far from the spinning axis the detonation fronts converge asynchronically at the antipodes of the igniting point. Nevertheless, the detonation of the carbon core still remains as the most probable outcome. The detonation of the core gives rise to a strong explosion, matching many of the basic observational constraints of Type Ia Supernova. We conclude that the Double Detonation mechanism also works when the white dwarf is spinning fast. This confirms the sub-Chandrasekhar-mass models and, maybe some Double Degenerate models (those having some helium fuel at the merging moment), as appealing channels to produce Type Ia Supernova events.