Supernova simulations from a 3D progenitor model - Impact of perturbations and evolution of explosion properties

We study the impact of large-scale perturbations from convective shell burning on the corecollapse supernova explosion mechanism using 3D multigroup neutrino hydrodynamics simulations of an 18M_⊙ progenitor. Seed asphericities in the O shell, obtained from a recent 3D model of O shell burning, help trigger a neutrino-driven explosion 330 ms after bounce whereas the shock is not revived in a model based on a spherically symmetric progenitor for at least another 300 ms. We tentatively infer a reduction of the critical luminosity for shock revival by ~20 per cent due to pre-collapse perturbations. This indicates that convective seed perturbations play an important role in the explosion mechanism in some progenitors. We follow the evolution of the 18M_⊙ model into the explosion phase for more than 2 s and find that the cycle of accretion and mass ejection is still ongoing at this stage. With a preliminary value of 7.7 × 10⁵⁰ erg for the diagnostic explosion energy, a baryonic neutron star mass of 1.85M_⊙, a neutron star kick of ~600 km s^-1 and a neutron star spin period of ~20 ms at the end of the simulation, the explosion and remnant properties are slightly atypical, but still lie comfortably within the observed distribution. Although more refined simulations and a larger survey of progenitors are still called for, this suggests that a solution to the problem of shock revival and explosion energies in the ballpark of observations is within reach for neutrino-driven explosions in 3D.