Dark matter effects on the properties of hybrid neutron stars

TL;DR

This paper investigates how dark matter influences the structure, stability, and phase transition properties of hybrid neutron stars, revealing that dark matter can lower the maximum mass and alter oscillation frequencies.

Contribution

It introduces a detailed two-fluid model coupling dark matter and nuclear matter, analyzing their combined effects on neutron star properties and phase transitions.

Findings

Dark matter decreases the critical mass for hadron-quark phase transition.

Presence of dark matter can trigger quark matter in accreting stars.

Dark matter significantly reduces radial oscillation frequencies.

Abstract

We study the effects of dark matter on the properties of hybrid neutron stars, in particular the influence on the mass-radius relation, the value of the maximum mass, and the hadron-quark phase transition. To single out the equilibrium configurations of dark-matter-admixed hybrid neutron stars (DHSs), we also study their radial oscillations. Both the stellar structure equations and the radial oscillation equations are solved for the two-fluid system, where the ordinary matter component and dark matter component couple only through gravity. For the ordinary matter components, we adopt the Brueckner-Hartree-Fock method for nuclear matter, and the Dyson-Schwinger or the field-correlator model for quark matter. For the dark matter component, we use a non-self-annihilating self-interacting fermionic model. We find that the presence of dark matter in DHSs leads to a decrease of the critical mass of the hadron-quark phase transition, a related possible onset of quark matter in dark-matter accreting stars, and a significant reduction of radial oscillation frequencies.