Strange Quark Stars and Spontaneous Scalarization

Abstract

Strange quark matter, as one of the most extreme dense states in astrophysics, can be explored through relativistic compact objects. Hypothetical relativistic stars composed of dense strange quark matter are characterized by the equation of state of that matter. The spontaneous scalarization of strange quark stars is influenced by the equation of state of strange quark matter. Here, we investigate how the equation of state of strange quark matter influences the spontaneous scalarization of these stars. Considering Normal, color-flavor-locked (CFL), and CFLm quark matter in the bag models and applying the scalar-tensor gravity, we calculate the structure of scalarized strange quark stars. We investigate how the effective bag constant, perturbative QCD parameter, CFL pairing gap, and strange quark mass control the mass-radius relation, the central scalar field, the scalarization thresholds, and the scalar charge. Our results demonstrate that strange quark stars in scalar-tensor gravity are viable, testable objects, and they establish a complete framework for constraining both the gravitational theory and the properties of cold quark matter with current and future multimessenger observations.

Comments: 39 pages, 19 figures. Accepted for publication in Physical Review D