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 IDSA for electron neutrinos and ASL 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 > 0.45) and low compactness (LC) (ξ 1.75 < 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 56 Ni and fallback is needed to reproduce the observed nucleosynthesis yields. 57−58 Ni 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.

In a previously presented proof-of-principle study, we established a parametrized spherically symmetric explosion method (PUSH) that can reproduce many features of core-collapse supernovae for a wide range of pre-explosion models. The method is based on the neutrino-driven mechanism and follows collapse, bounce and explosion. There are two crucial aspects of our model for nucleosynthesis predictions. First, the mass cut and explosion energy emerge simultaneously from the simulation (determining, for each stellar model, the amount of Fe-group ejecta). Second, the interactions between neutrinos and matter are included consistently (setting the electron fraction of the innermost ejecta). In the present paper, we use the successful explosion models from Ebinger et al. (2018) which include two sets of pre-explosion models at solar metallicity, with combined masses between 10.8 and 120 M . We perform systematic nucleosynthesis studies and predict detailed isotopic yields. The resulting 56 Ni ejecta are in overall agreement with observationally derived values from normal core-collapse supernovae. The Fe-group yields are also in agreement with derived abundances for metal-poor star HD 84937. We also present a comparison of our results with observational trends in alpha element to iron ratios.

In a previously presented proof-of-principle study we established a parametrized spherically symmetric explosion method (PUSH) that can reproduce many features of core-collapse supernovae. The present paper goes beyond a specific application that is able to reproduce observational properties of SN1987A and performs a systematic study of an extensive set of non-rotating, solar metallicity stellar progenitor models in the mass range from 10.8 to 120 M . This includes the transition from neutron stars to black holes as the final result of the collapse of massive stars, and the relation of the latter to supernovae, possibly faint supernovae, and failed supernovae. We discuss the explosion properties of all models and predict remnant mass distributions within this approach. The present paper provides the basis for extended nucleosynthesis predictions in a forthcoming paper to be employed in galactic evolution models.