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Register a new userPUSHing Core-Collapse Supernovae to Explosions in Spherical Symmetry II: Explodability and Global Properties
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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 the explosion properties for an extensive set of non-rotating, solar metallicity stellar progenitor models in the mass range from 10.8 to 120 M$_odot$.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 and faint/failed supernovae. The present paper provides the basis for extended nucleosynthesis predictions in a forthcoming paper to be employed in galactic evolution models.
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In this fourth paper of the series, we use the parametrized, spherically symmetric explosion method PUSH to perform a systematic study of two sets of non-rotating stellar progenitor models. Our study includes pre-explosion models with metallicities Z=0 and Z=Z$_{odot}times 10^{-4}$ and covers a progenitor mass range from 11 up to 75 M$_odot$. We present and discuss the explosion properties of all models and predict remnant (neutron star or black hole) mass distributions within this approach. We also perform systematic nucleosynthesis studies and predict detailed isotopic yields as function of the progenitor mass and metallicity. We present a comparison of our nucleosynthesis results with observationally derived $^{56}$Ni ejecta from normal core-collapse supernovae and with iron-group abundances for metal-poor star HD~84937. Overall, our results for explosion energies, remnant mass distribution, $^{56}$Ni mass, and iron group yields are consistent with observations of normal CCSNe. We find that stellar progenitors at low and zero metallicity are more prone to BH formation than those at solar metallicity, which allows for the formation of BHs in the mass range observed by LIGO/VIRGO.
Core-collapse supernovae (CCSNe) are the extremely energetic deaths of massive stars. They play a vital role in the synthesis and dissemination of many heavy elements in the universe. In the past, CCSN nucleosynthesis calculations have relied on artificial explosion methods that do not adequately capture the physics of the innermost layers of the star. The PUSH method, calibrated against SN1987A, utilizes the energy of heavy-flavor neutrinos emitted by the proto-neutron star (PNS) to trigger parametrized explosions. This makes it possible to follow the consistent evolution of the PNS and to ensure a more accurate treatment of the electron fraction of the ejecta. Here, we present the Iron group nucleosynthesis results for core-collapse supernovae, exploded with PUSH, for two different progenitor series. Comparisons of the calculated yields to observational metal-poor star data are also presented. Nucleosynthesis yields will be calculated for all elements and over a wide range of progenitor masses. These yields can be immensely useful for models of galactic chemical evolution.
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$_{odot}$. 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 HD84937. We also present a comparison of our results with observational trends in alpha element to iron ratios.
We present a comparison between several simulation codes designed to study the core-collapse supernova mechanism. We pay close attention to controlling the initial conditions and input physics in order to ensure a meaningful and informative comparison. Our goal is three-fold. First, we aim to demonstrate the current level of agreement between various groups studying the core-collapse supernova central engine. Second, we desire to form a strong basis for future simulation codes and methods to compare to. Lastly, we want this work to be a stepping stone for future work exploring more complex simulations of core-collapse supernovae, i.e., simulations in multiple dimensions and simulations with modern neutrino and nuclear physics. We compare the early (first ~500ms after core bounce) spherically-symmetric evolution of a 20 solar mass progenitor star from six different core-collapse supernovae codes: 3DnSNe-IDSA, AGILE-BOLTZTRAN, FLASH, F{sc{ornax}}, GR1D, and PROMETHEUS-VERTEX. Given the diversity of neutrino transport and hydrodynamic methods employed, we find excellent agreement in many critical quantities, including the shock radius evolution and the amount of neutrino heating. Our results provide an excellent starting point from which to extend this comparison to higher dimensions and compare the development of hydrodynamic instabilities that are crucial to the supernova explosion mechanism, such as turbulence and convection.
Understanding the properties of Pop III stars is prerequisite to elucidating the nature of primeval galaxies, the chemical enrichment and reionization of the early IGM, and the origin of supermassive black holes. While the primordial IMF remains unknown, recent evidence from numerical simulations and stellar archaeology suggests that some Pop III stars may have had lower masses than previously thought, 15 - 50 Ms in addition to 50 - 500 Ms. The detection of Pop III supernovae by JWST, WFIRST or the TMT could directly probe the primordial IMF for the first time. We present numerical simulations of 15 - 40 Ms Pop III core-collapse SNe done with the Los Alamos radiation hydrodynamics code RAGE. We find that they will be visible in the earliest galaxies out to z ~ 10 - 15, tracing their star formation rates and in some cases revealing their positions on the sky. Since the central engines of Pop III and solar-metallicity core-collapse SNe are quite similar, future detection of any Type II supernovae by next-generation NIR instruments will in general be limited to this epoch.
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