Thermal Relaxation of Dark Matter Admixed Neutron Star

TL;DR

This study investigates how dark matter within neutron stars influences their thermal evolution, showing that dark matter significantly affects neutrino emission, heat capacity, and cooling rates, aligning with observations of fast cooling in some stars.

Contribution

It introduces a detailed model of dark matter admixed neutron stars at finite temperature, analyzing their thermal properties and cooling behavior using relativistic mean-field formalism.

Findings

Dark matter increases neutrino emissivity and cooling rates.

Stars with higher dark matter momentum exhibit faster cooling.

The model aligns with observational data of rapid cooling in neutron stars.

Abstract

Motivated by the various theoretical studies regarding the efficient capturing of dark matter by neutron stars, we explore the possible indirect effects of captured dark matter on the cooling mechanism of a neutron star. The equation of states for different configurations of dark matter admixed star at finite temperature is obtained using the relativistic mean-field formalism with the IOPB-I parameter set. We show that the variation in the dark matter momentum vastly modifies the neutrino emissivity through specific neutrino generating processes of the star. The specific heat and the thermal conductivity of a dark matter admixed star have also been investigated to explore the propagation of cooling waves in the interior of the star. The dependence of theoretical surface temperature cooling curves on the equation of state and chemical composition of the stellar matter has also been discussed along with the observational data of thermal radiation from various sources. We observed that the dark matter admixed canonical stars with $k_{f}^{\rm DM} > 0.04$ comply with the fast cooling scenario. Further, the metric for internal thermal relaxation epoch has also been calculated with different dark matter momentum and we deduced that increment of dark matter segment amplify the cooling and internal relaxation rates of the star.