J. Phys. IV France 10 (2000) Pr5-467-Pr5-472
On the theory of supernova type la explosionM.A. Liberman
Department of Physics, Uppsala University, Box 530, 75121 Uppsala, Sweden, and P. Kapitsa Institute for Physical Problems, Russian Academy of Sciences, 117334 Moscow, Russia
A self-consistent model of white dwarf burning in Supernova Ia events is presented which includes the consequent stages of the flame, the spontaneous explosion and the detonation. The flame is ignited locally al several points near the center of the star. The formed bubbles of the light burnt matter together with the flame are pushed out of the center so that majority of the central part of the star remains unburnt by the flame, though the total mass burned by the flame till the time of the spontaneous explosion exceeds 0.1 of the white dwarf mass. The unburnt fuel explodes spontaneously after the time delay determined by the average temperature at the center of the star. The spontaneous explosion triggers the detonation, which incinerates the rest of the pre-expanded star. The expansion of the white dwarf during the flame stage of burning leads to the production of intermediate mass elements (S, Si, Ca etc.) in agreement with the observed spectrum. Stability analysis of the thermonuclear detonation in a white dwarf shows that the detonation is unstable and self-quenching at high densities of the degenerate matter ρ > 2,1.107 g/cm3 and it becomes stable at lower densities. The detonation overcomes gravitational binding and causes mass ejection. The proposed theory provides the physical basis for the explanation of the observed spectrum of Supernovae Ia.
© EDP Sciences 2000