May 21, 2024 | JIA JIE LI, ARMen SEDRAKIAN, MARK ALFORD
This paper investigates hybrid star models in light of new multi-messenger data, focusing on their ability to explain recent astrophysical observations of compact stars. Hybrid stars are proposed to have quark cores surrounded by nucleonic envelopes, and the study uses a family of 81 nucleonic equations of state (EoSs) with varying symmetry energy parameters and a constant sound speed EoS for quark matter. These models are tested against data from GW170817, J1731-347, J0592-0607, and J0740+6620, which favor different EoS characteristics. The results show that hybrid stars can account for the observed mass and radius ranges of these objects, with some models predicting maximum masses up to 2.6 solar masses. The study also examines twin configurations, where two stars have the same mass but different radii. It is found that hybrid stars with low transition densities can support twin configurations with masses less than 1.3 solar masses. The inclusion of J0592-0607's mass measurement does not significantly affect the parameter space of the admissible EoS, but allows for the exploration of more massive pulsars. The paper concludes that hybrid stars remain a viable model for dense matter and compact stars, and that the current data do not rule out their existence. The study also highlights the importance of considering both nucleonic and quark matter in understanding the properties of compact stars.This paper investigates hybrid star models in light of new multi-messenger data, focusing on their ability to explain recent astrophysical observations of compact stars. Hybrid stars are proposed to have quark cores surrounded by nucleonic envelopes, and the study uses a family of 81 nucleonic equations of state (EoSs) with varying symmetry energy parameters and a constant sound speed EoS for quark matter. These models are tested against data from GW170817, J1731-347, J0592-0607, and J0740+6620, which favor different EoS characteristics. The results show that hybrid stars can account for the observed mass and radius ranges of these objects, with some models predicting maximum masses up to 2.6 solar masses. The study also examines twin configurations, where two stars have the same mass but different radii. It is found that hybrid stars with low transition densities can support twin configurations with masses less than 1.3 solar masses. The inclusion of J0592-0607's mass measurement does not significantly affect the parameter space of the admissible EoS, but allows for the exploration of more massive pulsars. The paper concludes that hybrid stars remain a viable model for dense matter and compact stars, and that the current data do not rule out their existence. The study also highlights the importance of considering both nucleonic and quark matter in understanding the properties of compact stars.