On the Importance of the Equation of State for the Neutrino-Driven Supernova Explosion Mechanism

TL;DR

This study investigates how different equations of state (EOS) influence the dynamics of core-collapse supernovae in 1D and 2D simulations, revealing that EOS choice affects shock expansion and explosion energy, especially in multi-dimensional models.

Contribution

It provides a comparative analysis of LS and SHEN EOS impacts on supernova explosion mechanisms using advanced neutrino radiation hydrodynamics simulations.

Findings

1D simulations do not produce explosions with either EOS.

2D models show larger shock radii with LS EOS compared to SHEN.

LS EOS leads to more energetic and vigorous explosions in 2D models.

Abstract

By implementing widely-used equations of state (EOS) from Lattimer & Swesty (LS) and H. Shen et al. (SHEN) in core-collapse supernova simulations, we explore possible impacts of these EOS on the post-bounce dynamics prior to the onset of neutrino-driven explosions. Our spherically symmetric (1D) and axially symmetric (2D) models are based on neutrino radiation hydrodynamics including spectral transport, which is solved by the isotropic diffusion source approximation. We confirm that in 1D simulations neutrino-driven explosions cannot be obtained for any of the employed EOS. Impacts of the EOS on the post-bounce hydrodynamics are more clearly visible in 2D simulations. In 2D models of a 15 M_sun progenitor using the LS EOS, the stalled bounce shock expands to increasingly larger radii, which is not the case using the SHEN EOS. Keeping in mind that the omission of the energy drain by heavy-lepton neutrinos in the present scheme could facilitate explosions, we find that 2D models of an 11.2 M_sun progenitor produce neutrino-driven explosions for all the EOS under investigation. Models using the LS EOS are slightly more energetic compared to those with the SHEN EOS. The more efficient neutrino heating in the LS models coincides with a higher electron antineutrino luminosity and a larger mass that is enclosed within the gain region. The models based on the LS EOS also show a more vigorous and aspherical downflow of accreting matter to the surface of the protoneutron star (PNS). The accretion pattern is essential for the production and strength of outgoing pressure waves, that can push in turn the shock to larger radii and provide more favorable conditions for the explosion. [abbreviated]