"Multiphysics Models of Binary White Dwarf Mergers"

Daniel Fenn
Department of Scientific Computing
Florida State University

Wednesday, April 13, 2016 -- 3:30 P.M. 499 Dirac Science Library

Abstract:

Though decades of research into Type Ia supernovae have provided a significant quantity of information, critical details concerning the origins of these thermonuclear events are still missing. A popular theory, termed the double degenerate scenario, holds that these events arise from the mergers of white dwarfs in a close binary system. Previous work in this field has utilized either the smoothed-particle hydrodynamics (SPH) method, which may under-resolve important physical processes, or hybrid SPH/grid methods, which may introduce numerical artifacts.

In this presentation, we discuss our study of the white dwarf merger process at early times. This includes examination of the possibility of prompt ignition, in which a runaway fusion reaction is initiated in the early merger stages. We present, for the first time, a set of merger simulations solely performed using a grid-based hydrocode in three dimensions. We consider systems with differing mass ratios and compositions, and total mass exceeding the Chandrasekhar mass. We discuss the conditions required for the initiation and sustaining of a detonation, and analyze simulation results in detail, describing the observed regimes of thermonuclear burning.