How does dark matter affect compact star properties and high density constraints of strongly interacting matter

¹ CFisUC, Department of Physics, University of Coimbra, Rua Larga P-3004-516, Coimbra, Portugal
² Institute of Theoretical Physics, University of Wroclaw, 50-204 Wroclaw, Poland
³ Institut für Physik und Astronomie, Universität Potsdam, Haus 28, Karl-Liebknecht-Str. 24/25, Potsdam, Germany
⁴ Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg 1, Potsdam, Germany

^* e-mail: violetta.sagun@uc.pt
^** e-mail: eg@student.uc.pt
^*** e-mail: oleksii.ivanytskyi@uwr.edu.pl
^**** e-mail: cp@uc.pt
^† e-mail: tim.dietrich@aei.mpg.de

Published online: 22 December 2022

Abstract

We study the impact of asymmetric bosonic dark matter on neutron star properties, including possible changes of tidal deformability, maximum mass, radius, and matter distribution inside the star. The conditions at which dark matter particles tend to condensate in the star’s core or create an extended halo are presented. We show that dark matter condensed in a core leads to a decrease of the total gravitational mass and tidal deformability compared to a pure baryonic star, which we will perceive as an effective softening of the equation of state. On the other hand, the presence of a dark matter halo increases those observable quantities. Thus, observational data on compact stars could be affected by accumulated dark matter and, consequently, constraints we put on strongly interacting matter at high densities. To confirm the presence of dark matter in the compact star’s interior, and to break the degeneracy between the effect of accumulated dark matter and strongly interacting matter properties at high densities, several astrophysical and GW tests are proposed.