PUSHing Core-collapse Supernovae to Explosions in Spherical Symmetry. V. Equation of State Dependency of Explosion Properties, Nucleosynthesis Yields, and Compact Remnants

Abstract

In this fifth paper of the series, we use the parameterized, spherically symmetric explosion method PUSH to investigate the impact of eight different nuclear equations of state (EOS). We present and discuss the explosion properties and the detailed nucleosynthesis yields, and predict the remnant (neutron star or black hole) for all our simulations. For this, we perform two sets of simulations. First, a complete study of nonrotating stars from 11 to 40 M ⊙ at three different metallicities using the SFHo EOS; and, second, a suite of simulations for four progenitors (16 M ⊙ at three metallicities and 25 M ⊙ at solar metallicity) for eight different nuclear EOS. We compare our predicted explosion energies and yields to observed supernovae and to the metal-poor star HD 84937. We find EOS-dependent differences in the explosion properties and the nucleosynthesis yields. However, when comparing to observations, these differences are not large enough to rule out any EOS considered in this work.

Correlations ofr-process elements in very metal-poor stars as clues to their nucleosynthesis sites

“…The production of Sr, Y, Zr, and even heavier elements below the A = 130 peak seems possible in a combination of a νp-process (e.g., Fröhlich et al 2006;Eichler et al 2018) and a (very) weak r-process (Wanajo et al 2018;Curtis et al 2019), for the latter see also Kratz et al (2007), Farouqi et al (2009), andAkram et al (2020), but Eu seems not to be produced. An excellent update on this situation is recently provided by Ghosh et al (2022). This would exclude within our present understanding a weak r-process Eu production in regular CCSNe, opposite to category I or II events.…”

“…When focusing on the Fe-group elements we tried to be already more concrete and pointed to stellar core collapse with varying initial stellar masses. We also mentioned that even in the case of regular (neutrino-driven) core-collapse supernovae, due to Y e -variations in the ejecta (see e.g., Ghosh et al 2022), light trans-Fe elements such as Sr, Y, and Zr and even elements up to the second r-process peak can be produced. We introduced for these sources category 0 events.…”

“…For this behavior, one can introduce an additional category 0, coproducing with Fe also light trans-Fe elements, possibly even up to the second r-process peak (see e.g., Fig. 10 in Ghosh et al 2022), but not contributing up to Eu. Therefore, regular CCSNe are clear candidates.…”

“…Out of these sites (a) might provide the conditions for a very weak r-process and νp-process, whether only up to Sr, Y, Zr or up to (but not beyond) the A = 130 peak is still debated (Wanajo et al 2018;Curtis et al 2019;Fischer et al 2020a;Ghosh et al 2022). (b) is a class of supernovae whose existence is put into question after recent re-determinations of the electron capture rate of 20 Ne (Kirsebom et al 2019a,b), but is not firmly excluded, however, leading to a too strong decline in abundances as a function of A for realistic Y e -conditions (Wanajo et al 2011).…”

“…Arcones & Montes 2011;Arcones & Thielemann 2013;Akram et al 2020). In fact, recent core-collapse supernova investigations byGhosh et al (2022) find across the mass spectrum of CCSNe a superposition of νp-process contributions up to A ≈ 60−70 and a (very) weak r-process contribution up to the second r-process peak at A = 130, but not beyond.…”