Pushing Core-Collapse Supernovae to Explosions in Spherical Symmetry. I. The Model and the Case of Sn 1987a

Abstract

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.

The Multi-dimensional Character of Core-collapse Supernovae

“…For example, much of the study of nucleosynthesis from CCSN is based on 1D models that replace the inner workings of the supernova with a kinetic energy piston (see, e.g., [18,19,20]) or a thermal energy bomb (see, e.g., [21,24]). While improved models are being developed (see, e.g., [22,23]), seeking to incorporate the lessons we have learned in the past two decades about the nature of these neutrino-driven, hydrodynamically unstable explosions, the relatively low computational cost of the bomb/piston models allows grids of hundreds of models to be prepared to serve as input to galactic chemical evolution studies. More ambitious models that include multi-dimensional fluid flow and neutrino transport are needed to explore more fundamental questions about the nature of the CCSN mechanism.…”

On Variations of Pre-Supernova Model Properties

“…One end state, core-collapse SN, is the result of another end state, massive star progenitors undergoing gravitational collapse (e.g., Sukhbold & Woosley 2014;Perego et al 2015;Sukhbold et al 2016). The amount of mass of an isotope that can be injected into the interstellar medium (e.g., Limongi & Chieffi 2003;Nomoto et al 2013) depends on the structure of the star at the point of core-collapse.…”

Nucleosynthesis in 2D Core-Collapse Supernova Long-Term Simulations of 11.2 and 17.0 \(\text{M}_{ \odot }\) Progenitors

“…The reaction rates employed for this study are the same as in [4]. All the tracer trajectories are individually extrapolated until the temperature drops below T 9 = 0.01, using an adiabatic expansion with constant velocity.…”