Dark-Matter Admixed Neutron Stars

TL;DR

This paper explores the structure and stability of neutron stars containing a dark matter component, revealing a new class of compact stars with a normal matter core and a dark matter halo, potentially observable as unusual small neutron stars.

Contribution

It introduces a relativistic two-fluid model for dark matter admixed neutron stars and demonstrates their stability and unique mass-radius configurations.

Findings

Discovery of a new class of compact stars with dark matter halos.

Mass-radius relations differ significantly from traditional neutron stars.

Stable configurations with small normal matter cores and dark matter halos.

Abstract

We study the hydrostatic equilibrium configuration of an admixture of degenerate dark matter and normal nuclear matter by using a general relativistic two-fluid formalism. We consider non- self-annihilating dark matter particles of mass ~ 1 GeV. The mass-radius relations and moments of inertia of these dark-matter admixed neutron stars are investigated and the stability of these stars is demonstrated by performing a radial perturbation analysis. We find a new class of compact stars which consists of a small normal matter core with radius of a few km embedded in a ten-kilometer- sized dark matter halo. These stellar objects may be observed as extraordinarily small neutron stars that are incompatible with realistic nuclear matter models.