Friedrich Roepke - March 16, 2018

Simulations of Type Ia supernova explosions

Type Ia supernovae are among the most prominent cosmic explosions in the 
current universe. Because of their extreme brightness and correlations 
between observable properties that allow for a calibration as distance 
indicators, they have been instrumental in surveying its geometry. At 
the same time, these explosions are prolific sources of iron group 
elements and shape the chemical structure of their host galaxies. 
Despite their significance for various astrophysical processes, 
the mechanism of Type Ia supernovae remains enigmatic. A fundamental 
handicap for model building is the unknown nature of the progenitor 
system. Several distinct scenarios are currently discussed involving 
explosions of Chandrasekhar-mass and sub-Chandrasekhar mass white 
dwarf stars. These can be tested in numerical simulations, provided 
that uncertainties in the physical explosion mechanism and numerical 
approximations can be controlled. This is a very challenging task 
because of the pronounced multi-scale multi-physics character of 
the explosion process. Nonetheless, significant progress was possible 
with multidimensional hydrodynamic explosion simulations, that 
provide the basis for the prediction of observables. I will review 
the involved challenges, describe possible approaches to model building 
and numerical implementation, and give examples for simulations of 
thermonuclear supernova explosions in different scenarios. Finally, 
I will discuss achievements and shortcomings of current multidimensional 
models and outline paths to validate them based on comparison with 
various observational data.