Regular Article - Theoretical Physics
GW170817 and GW190425 as hybrid stars of dark and nuclear matter
Department of Physics, National Taiwan Normal University, 11677, Taipei, Taiwan
2 Department of Physics, Shanghai University, 200444, Shanghai, Mainland, China
3 Shanghai Key Lab for Astrophysics, 200234, Shanghai, Mainland, China
4 Center of Astronomy and Gravitation, National Taiwan Normal University, 11677, Taipei, Taiwan
Accepted: 19 April 2022
Published online: 26 April 2022
We propose three scenarios for compact hybrid stars composed of nuclear and dark matter. These hybrid stars could provide alternative interpretations to the LIGO/Virgo events GW170817 and GW190425. To demonstrate our proposal, we solve the Tolman–Oppenheimer–Volkoff configurations of hybrid stars by using the SLy4, APR4, and SKb equations of state (EoS) for nuclear matter, and an EoS for a bosonic self interacting dark matter (SIDM) proposed by Colpi et al. (Phys Rev Lett 57:2485, 1986). We then obtain their mass–radius and tidal Love number (TLN)-mass relations, and further examine the possible saddle instability of these compact objects by the generalized Bardeen–Thorne–Meltzer (BTM) criteria. Our results show that the hybrid star scenarios are able to explain GW170817 and GW190425. Some hybrid stars can have compact neutron or mixed cores around 10 km while possessing thick dark matter shells, thus they can be more massive than the maximum mass of the typical neutron stars but are electromagnetically detected with about the same size of neutron stars. Reversely, we also infer the dark matter model from the parameter estimation of GW190425. Our proposed hybrid stars can be further tested by the coming LIGO/Virgo O3 events.
© The Author(s) 2022
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