The Second Love Number of Dark Compact Planets and Neutron Stars with Dark Matter

TL;DR

This paper investigates how dark matter influences the physical properties of compact objects, revealing potential observational signatures in gravitational wave data that could confirm dark matter presence inside neutron stars.

Contribution

It introduces models of dark matter admixed compact objects and analyzes their mass-radius relation and tidal deformability, highlighting observable differences from standard neutron stars.

Findings

Stable dark matter admixed objects with radii <10 km and Earth- or Jupiter-like masses.

Second Love numbers can significantly differ due to dark matter, affecting tidal deformability.

Gravitational wave measurements could detect dark matter signatures inside neutron stars.

Abstract

We study the mass-radius relation and the second Love number of compact objects made of ordinary matter and non-selfannihilating fermionic dark matter for a wide range of dark matter particle masses, and for the cases of weakly and strongly interacting dark matter. We obtain stable configurations of compact objects with radii smaller than 10 km and masses similar to Earth- or Jupiter-like stellar objects. In certain parameter ranges we find second Love numbers which are markedly different compared to those expected for neutron stars without dark matter. Thus, by obtaining the compactness of these compact objects and measuring their tidal deformability from gravitational wave detections from binary neutron star mergers, the extracted value of second Love number would allow to determine the existence of dark matter inside neutron stars irrespective of the equation of state of ordinary matter.