Friday

The ‘double detonation’ explosion mechanism is a promising progenitor scenario for Type Ia supernovae. In this scenario, helium accreted onto the surface of a sub-Chandrasekhar mass white dwarf detonates, leading to a second carbon detonation in the WD core. We present radiative transfer simulations for a new parameter study of 3D hydrodynamical simulations of the double detonation scenario, where we have investigated the sensitivity to the core and shell masses. The core masses range from 0.8 M⊙ to 1.0 M⊙ and the shell masses range from 0.02 M⊙ to 0.1 M⊙. These models show a wide range of brightnesses, with peak absolute B-band magnitudes ranging from -16.1 to -19.9 mag, and are able to account for the brightnesses of the main classes of SNe Ia. We find that all of our models show strong absorption features due to the helium shell detonation products, even those with low mass helium shells. The models show strong viewing angle dependencies, in agreement with previous findings, such that at one extreme we find line blanketing of the spectra at blue wavelengths, and in the opposite direction we find minimal absorption features due to the helium ash. We make comparisons with observations of SNe Ia and comment on the ability of the double detonation scenario to account for normal and peculiar SNe Ia. We also discuss the effect of treating the radiative transfer calculations in non-local thermodynamic equilibrium, and how this affects the comparison of simulations with observations.