# Cooling of neutron stars with stiff stellar matter

## TL;DR

This paper investigates the thermal evolution of neutron stars with stiff hadronic matter equations of state, using nuclear medium cooling models to explain observational data on star temperatures and ages.

## Contribution

It applies the nuclear medium cooling scenario to stiff EoS models, including effects like pion softening, to match observational data on neutron star cooling.

## Key findings

- Stiff EoS models can explain observed neutron star temperatures.
- In-medium effects are crucial for accurate cooling predictions.
- Excluded volume corrections influence the thermal evolution results.

## Abstract

Recent evidence for high masses ($\sim 2~ M_\odot$) pulsars PSR J1614-2230 and PSR J0348-0432 requires neutron star matter to have a stiff equation of state (EoS). The thermal evolution of compact stars (CS) with stiff hadronic EoS necessitates the application of the "nuclear medium cooling" scenario with a selection of appropriate proton gap profiles together with in-medium effects (like pion softening) on cooling mechanisms in order to achieve a satisfactory explanation of all existing observational data for the temperature-age relation of CS. Here we focus on two examples from \cite{Grigorian:2016leu} for a stiff hadronic EoS without (DD2 EoS) and with (DD2vex) excluded volume correction.