Finite-temperature equation of state with hyperons

TL;DR

This paper introduces a new finite-temperature equation-of-state model including hyperons, crucial for understanding proto-neutron stars, mergers, and supernovae, highlighting the importance of temperature effects on thermodynamics and composition.

Contribution

The novel FSU2H* model incorporates hyperons at finite temperatures, providing a comprehensive tool for astrophysical simulations of dense stellar objects.

Findings

Hyperons significantly influence thermodynamical properties at finite temperature.

The thermal index varies with temperature and density when hyperons are included.

Constant gamma laws cannot accurately reproduce true thermal effects with hyperons.

Abstract

We present the novel finite-temperature FSU2H$^*$ equation-of-state model that covers a wide range of temperatures and lepton fractions for the conditions in proto-neutron stars, neutron star mergers and supernovae. The temperature effects on the thermodynamical observables and the composition of the neutron star core are stronger when the hyperonic degrees of freedom are considered. We pay a special attention to the temperature and density dependence of the thermal index in the presence of hyperons and conclude that the true thermal effects cannot be reproduced with the use of a constant $\Gamma$ law.