Late‐Time Convection in the Collapse of a 23M⊙Star

The results of a 3-dimensional SNSPH simulation of the core collapse of a 23solar mass star are presented. This simulation did not launch an explosionuntil over 600ms after collapse, allowing an ideal opportunity to study theevolution and structure of the convection below the accretion shock to latetimes. This late-time convection allows us to study several of the recentclaims in the literature about the role of convection: is it dominated by anl=1 mode driven by vortical-acoustic (or other) instability, does it producestrong neutron star kicks, and, finally, is it the key to a new explosionmechanism? The convective region buffets the neutron star, imparting a 150-200km/s kick. Because the l=1 mode does not dominate the convection, the neutronstar does not achieve large (>450 km/s) velocities. Finally, the neutron starin this simulation moves, but does not develop strong oscillations, the energysource for a recently proposed supernova engine. We discuss the implicationsthese results have on supernovae, hypernovae (and gamma-ray bursts), andstellar-massed black holes.Comment: 31 pages (including 13 figures), submitted to Ap