Supernova nucleosynthesis as a tool to analyze the explosion mechanism
F.-K. Thielemann, F. Brachwitz, C. Freiburghaus, T. Rauscher, K. Iwamoto,
K. Nomoto, M. Hashimoto, W. R. Hix;
in "Nuclear Astrophysics", eds. M. Buballa, W. Noerenberg, J. Wambach,
A. Wirzba (GSI, Darmstadt 1998), p. 164.
Type II supernovae (SNe II) are linked to the gravitational collapse of
massive stars (M>8M_s) at the end of their hydrostatic evolution. The
resulting central hot proto-neutron star cools via neutrino emission.
Neutrino opacities and transport determine the neutrino emission
luminosity, which, together with the neutrino heating efficiency in
adjacent layers, is responsible for the explosion and ejection of
matter. This affects the nucleosynthesis products via two main
uncertainties, (i) the locations of the mass cut between the ejecta and
the remaining neutron star and (ii) the total explosion energy
responsible for explosive nucleosynthesis. Thus, observations can
constrain these quantities.
Type Ia supernovae (SNe Ia) are explained by exploding white dwarfs in
binary stellar systems. The favored systems are accreting white dwarfs,
approaching the (maximum stable) Chandrasekhar mass before contraction
and central ignition. Their major uncertainties are related (i) to the
accretion rate in the binary system which determines the carbon ignition
density and (ii) the flame speed after central ignition. We provide
several new constraints to the "average" SNe Ia systems, representing
the major source of Fe-group nuclei in the Galaxy.