The Mechanism of Core-Collapse Supernova Explosions: A Status Report

Abstract

Most massive stars (8 Mȯ → 80 Mȯ) must transition at the ends of their lives into neutron stars or stellar-mass black holes. That they do so when their low-entropy cores reach the Chandrasekhar mass, gravitationally collapse, and launch a supernova explosion has been demonstrated both by direct observations (cf., the neutrinos from SN1987A) and by a host of compelling theoretical arguments. However, numerical simulations of the process of core collapse, bounce near nuclear densities, shock wave generation, and shock propagation have failed to recreate in detail the observed gravitational masses of known neutron stars, the expected nucleosynthesis pattern, and empirical supernova energies. All semi-realistic, one-dimensional (spherically-symmetric) simulations conducted to date fizzle into quasi-static accreting proto-black holes. What is more, they seem to do so convincingly, despite concerted attempts over the years to include all the known neutrino and nuclear physics or general relativity [3,20,4,5,18,16,17,22]. It is now fairly clear that the devil is not "in the details" and that 1D models don't explode. Something large and major, not something at the "10-20% level," would have to be missing to alter this conclusion.