A New Open-Source Nuclear Equation of State Framework based on the Liquid-Drop Model with Skyrme Interaction

TL;DR

This paper introduces an open-source framework for nuclear equations of state using Skyrme interactions and a liquid-drop model, enabling flexible simulations of dense astrophysical matter.

Contribution

It provides a new set of finite temperature EOSs based on Skyrme forces and an open-source code for their calculation, enhancing modeling capabilities for astrophysical phenomena.

Findings

Skyrme parametrizations significantly affect neutron star properties.

The EOS framework captures phase transitions at sub-saturation densities.

Variations in microphysics influence core-collapse supernova outcomes.

Abstract

The equation of state (EOS) of dense matter is an essential ingredient for numerical simulations of core-collapse supernovae and neutron star mergers. The properties of matter near and above nuclear saturation density are uncertain, which translates into uncertainties in astrophysical simulations and their multi-messenger signatures. Therefore, a wide range of EOSs spanning the allowed range of nuclear interactions are necessary for determining the sensitivity of these astrophysical phenomena and their signatures to variations in input microphysics. We present a new set of finite temperature EOSs based on experimentally allowed Skyrme forces. We employ a liquid drop model of nuclei to capture the non-uniform phase of nuclear matter at sub-saturation density, which is blended into a nuclear statistical equilibrium EOS at lower densities. We also provide a new, open-source code for calculating EOSs for arbitrary Skyrme parametrizations. We then study the effects of different Skyrme parametrizations on thermodynamical properties of dense astrophysical matter, the neutron star mass-radius relationship, and the core collapse of 15 and 40 solar mass stars.