PUSHing Core-collapse Supernovae to Explosions in Spherical Symmetry I: the Model and the Case of SN 1987A

We report on a method, PUSH, for artificially triggering core-collapse supernova explosions of massive stars in spherical symmetry. We explore basic explosion properties and calibrate PUSH to reproduce SN 1987A observables. Our simulations are based on the GR hydrodynamics code AGILE combined with the neutrino transport scheme isotropic diffusion source approximation for electron neutrinos and advanced spectral leakage for the heavy flavor neutrinos. To trigger explosions in the otherwise non-exploding simulations, the PUSH method increases the energy deposition in the gain region proportionally to the heavy flavor neutrino fluxes. We explore the progenitor range 18-21 {{M}}⊙ . Our studies reveal a distinction between high compactness (HC; compactness parameter {ξ }1.75\gt 0.45) and low compactness (LC; {ξ }1.75\lt 0.45) progenitor models, where LC models tend to explode earlier, with a lower explosion energy, and with a lower remnant mass. HC models are needed to obtain explosion energies around 1 Bethe, as observed for SN 1987A. However, all the models with sufficiently high explosion energy overproduce 56Ni and fallback is needed to reproduce the observed nucleosynthesis yields. 57-58Ni yields depend sensitively on the electron fraction and on the location of the mass cut with respect to the shell structure of the progenitor. We identify a progenitor and a suitable set of parameters that fit the explosion properties of SN 1987A assuming 0.1 {{M}}⊙ of fallback. We predict a neutron star with a gravitational mass of 1.50 {{M}}⊙ . We find correlations between explosion properties and the compactness of the progenitor model in the explored mass range. However, a more complete analysis will require exploring of a larger set of progenitors.