Impact of the nuclear equation of state on the explodability of massive stars

Abstract

In recent years, astrophysical observations have placed tight constraints on key properties of the nuclear equation of state (EoS). Using 45 two-dimensional simulations for three different EoS compatible with the current tight constraints, we show that the EoS remains a major uncertainty for the outcome of core-collapse supernovae. Whereas explosions are obtained in most cases for the SFHo and SFHx EoS, for the CMF EoS, which includes a crossover from nucleonic matter to a quark phase, explosions occur only for 2 out of 15 progenitors. Less favourable conditions for neutrino-driven explosions arise for the CMF EoS due to lower neutrino luminosities and mean energies and slightly weaker contraction of the warm proto-neutron star. Our results suggest that the explodability of massive stars cannot yet be predicted based on first principles without better knowledge of the nuclear EoS. Conversely, observational constraints on stellar explodability may help further constrain the EoS.

Figures (3)

• Figure 1: The timescale criterion $\tau_{adv} / \tau_{heat}$ for the non-exploding CMF models (left), SFHo models (middle), and SFHx models (right). Rapid increase above 1 usually indicates neutrino-driven runaway shock expansion. However, the models with values above 1 formed black holes before shock revival could occur.
• Figure 2: A comparison of the underlying differences between the different EoS for the s12 model. Top left is the heating ratio. Top right is the shock and gain radius. Bottom left is shows the neutrino luminosity. Bottom right is the neutrino mean energy.
• Figure 3: The evolution of the PNS radius (top row), and the PNS mass (bottom row), for all models. From left to right are the CMF, SFHo and SFHx models. The highest mass CMF models form a black hole before the simulation end time. The s36.61 and s18 SFHo models also form a black hole before the simulation end time.