Ken J. Shen, Lars Bildsten
The progenitor channel responsible for the majority of Type Ia supernovae is still uncertain. One emergent scenario involves the detonation of a He-rich layer surrounding a C/O white dwarf, which sends a shock wave into the core. The quasi-spherical shock wave converges and strengthens at an off-center location, forming a second, C-burning, detonation that disrupts the whole star. In this paper, we examine this second detonation of the double detonation scenario using a combination of analytic and numeric techniques. We perform a spatially resolved study of the imploding shock wave and outgoing detonation and calculate the critical imploding shock strengths needed to achieve a core C detonation. We find that He detonations in recent two-dimensional simulations yield converging shock waves that are strong enough to ignite C detonations in C/O cores, with the caveat that a truly robust answer requires multi-dimensional detonation initiation calculations. We also find that, due to the greatly increased difficulty of igniting O-burning, convergence-driven detonations in O/Ne cores are far harder to achieve and are perhaps unrealized in standard binary evolution.
View original:
http://arxiv.org/abs/1305.6925
No comments:
Post a Comment