Axisymmetric neutrino radiation and the mechanism of supernova explosions

Numerical simulations of convection in the supernova core were carried out in which axisymmetrically modified neutrino radiation from a rotating proto-neutron star was assumed. Since neutrinos heat up matter around the rotational axis more intensively than around the equatorial plane, powerful and global convection of matter between the shock front and the proto-neutron star is induced, and, moreover, jetlike motion along the axis pushes the shock front into the prolate form. It is found that the hot bubble is distorted as a result of this quadrupolar convective motion and consequently that turbulent instability occurs behind the shock wave. This instability is considered to provide the initial fluctuation of Rayleigh-Taylor instability in the envelope, the seed of matter mixing in SN 1987A. We also found that three outstanding problems, namely, the seed of matter mixing, the high-velocity component of mixed elements, and observed asymmetry in the envelopes, can be explained simultaneously by those effects. Based on these results, we propose a new, possible scenario for the explosion mechanism.