Type Ia supernova explosion models

Because calibrated light curves of type Ia supernovae have become a major t ool to determine the local expansion rate of the universe and also its geom etrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe th at perhaps most type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M-chan approximate to 1.39 Mo-., an d are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continu es to be uncertain. Recent progress in modeling type Ia supernovae as well as several of the still open questions are addressed in this review. Althou gh the main emphasis is on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.