Particle and Flames in Radiative and Magnetic Flows

October 11-15, 2010
Lyon, France

Contribution of F. Roepke


Multi-dimensional simulations of thermonuclear explosions in different Type Ia supernova scenarios




Recent advances in observational techniques -- in particular, the dawn of extensive transient surveys -- revealed that significant diversity among Type Ia supernovae (SNe Ia). This suggests that a variety of progenitor channels and or explosion mechanisms contributes to this class of objects. Understanding the origin of the diversity is essential for applying SNe Ia as distance indicators in cosmology. Only multi-dimensional simulations of SN Ia explosions allow for a consistent treatment of the underlying physical mechanisms. Consequently, their predictive power enables a direct comparison with observations and, this way, the validity of different explosion scenarios can be assessed. Based on a comprehensive sequence of modeling taking into account aspects of population synthesis, multi-dimensional hydrodynamic explosion simulations, nucleosynthetic postprocessing and radiative transfer calculations, I will discuss the capability of different explosion scenarios to reproduce SN Ia observations. Although traditional Chandrasekhar mass models are promising candidates for explaining "normal" SNe Ia, their progenitors may not be numerous enough to account for their rate. Sub-Chandrasekhar mass explosions of white dwarfs provide a potential alternative. The observables predicted for violent mergers of two white dwarfs, however, resemble a class of sub-luminous SNe Ia rather than the bulk of normal events. An accurate modeling of burning fronts and the nucleosynthesis in the explosions is found to be critical for the predicted observables and thus for validating SN Ia models.