Massive relativistic compact stars from SU(3) symmetric quark models

We construct a set of hyperonic equations of state (EoS) by assuming SU(3) symmetry within the baryon octet and by using a covariant density functional (CDF) theory approach. The low-density regions of our EoS are constrained by terrestrial experiments, while the high-density regime is modeled by systematically varying the nuclear matter skewness coefficient Q(sat) and the symmetry energy slope L-sym. The sensitivity of the EoS predictions is explored in terms of z parameter of the SU(3) symmetric model that modifies the meson-hyperon coupling constants away from their SU(6) symmetric values. Our results show that model EoS based on our approach can support static Tolman-Oppenheimer-Volkof (TOV) masses in the range 2.3-2.5 M-circle dot in the large-Q(sat) and small-z regime, however, such stars contain only a trace amount of hyperons compared to SU(6) models. We also construct uniformly rotating Keplerian configurations for our model EoS for which the masses of stellar sequences may reach up to 3.0 M-circle dot. These results are used to explore the systematic dependence of the ratio of maximum masses of rotating and static stars, the lower bound on the rotational frequency of the models that will allow secondary masses in the gravitational waves events to be compact stars with M-2 less than or similar to 3.0M(circle dot) and the strangeness fraction on the model parameters. We conclude that very massive stellar models can be, in principle, constructed within the SU(3) symmetric model, however, they are nucleonic-like as their strangeness fraction drops below 3%. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

A set of hyperonic equations of state (EoS) are constructed by assuming SU(3) symmetry and using a covariant density functional theory approach. The EoS is constrained by terrestrial experiments at low density and modeled by varying the nuclear matter skewness coefficient and symmetry energy slope at high density. The results show that the model can support a range of static and rotating stellar masses under certain conditions.