The First Second of a Type II Supernova: Convection, Accretion, and Shock Propagation

Abstract

One- and two-dimensional hydrodynamical simulations of the neutrino-driven supernova explosion of a 15 M☉ star are performed for the phase between stagnation of the prompt shock and 1 s after core bounce. Variation of the neutrino (ν) fluxes from the ν sphere shows that explosion energy and timescale, initial proto-neutron star mass, and explosive nucleosynthesis of Fe group elements depend sensitively on the strength of the ν heating during the first few 100 ms after shock formation. Convective overturn in the ν-heated region behind the shock is a crucial help for the explosion only in a narrow window of ν luminosities. Here powerful explosions can be obtained only in the multidimensional case, primarily because the overturn increases the efficiency of ν energy deposition by allowing cool postshock matter to penetrate inward to the region of strongest heating, while heated gas can quickly rise outward, thus reducing its energy loss due to reemission of neutrinos. This interpretation is supported by the different increase of the explosion energy with time in one- and two-dimensional models. For higher core ν fluxes spherically symmetrical models also yield energetic explosions, while for lower luminosities even with convection, no strong explosions occur.

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• The Astrophysical Journal - View
• arXiv (Cornell University) - View - PDF
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