Dark Matter Effects on Compact Binary Stars

Abstract

As compact binary star systems move inside the halo of the galaxies, they interact with dark matter particles. The interaction between dark matter particles and baryonic matter causes dark matter particles to lose some part of their kinetic energy. Once dark matter particles lose part of their kinetic energy, they are gravitationally bound to stars, and stars start to absorb dark matter particles from the halo. The absorption of dark matter particles inside compact binary systems increases the mass of the binary components, and then the total mass of the binary systems increases as well. According to Kepler's third law, increased mass through this way can affect other physical parameters (e.g., semi-major axes and orbital periods) of these systems too. We estimate the period change of some known compact binary systems due to the accretion of dark matter particles into them. We investigate the effects of different dark matter particle candidates with masses in the range $\simeq 10^{-9} - 10^{5} \: (GeV.c^{-2})$ and dark matter density as high as the dark matter density near the Galactic central regions. We find that the estimated change of period due to the accretion of dark matter particles into compact binary systems can be as large as the measured values for these systems.