Type Ia Supernovae: Influence of the Initial Composition on the Nucleosynthesis, Light Curves, Spectra and Consequences for the Determination of Omega_M & Lambda

Abstract

The influence of the initial composition of the exploding white dwarf on the nucleosynthesis, light curves and spectra of Type Ia supernovae has been studied in order to evaluate the size of evolutionary effects on cosmological time scales, how the effects can be recognized and how one may be able to correct for them. The calculations are based on a set of delayed detonation models which give a good account of the optical and infrared light curves and of the spectral evolution. The explosions and light curves are calculated using a one- dimensional Lagrangian radiation-hydro code including a nuclear network. NLTE- spectra are computed for various epochs using the structure resulting from the light curve code. The following questions are addressed : What do we learn about the progenitor evolution and its metallicity? What are the systematic effects for the determination of the cosmological parameters $\Omega_M$ and $\Lambda$ and how can we recognize this potential 'pitfalls' and correct for evolutionary effects?