Properties of Neutron Stars Described by a Relativistic Ab Initio Model

Abstract

Abstract Properties of neutron stars are investigated by an available relativistic ab initio method, the relativistic Brueckner–Hartree–Fock (RBHF) model, with the latest high-precision, relativistic charge-dependent potentials, pvCD-Bonn A, B, C. The neutron star matter is solved within the beta equilibrium and charge neutrality conditions in the framework of the RBHF model. Compared to the conventional treatment, where the chemical potential of leptons was approximately represented by the symmetry energy of nuclear matter, the equation of state of neutron star matter in the present self-consistent calculation with pvCD-Bonn B has a striking difference above the baryon number density n b  = 0.55 fm−3. However, these differences influence the global properties of neutron stars only about 1% to 2%. Then, three two-body potentials pvCD-Bonn A, B, C, with different tensor components, are systematically applied in the RBHF model to calculate the properties of neutron stars. It is found that the maximum masses of neutron stars are around 2.21–2.30 M ⊙, and the corresponding radii are R = 11.18–11.72 km. The radii of a 1.4 M ⊙ neutron star are predicated as R 1.4 = 12.34–12.91 km, and their dimensionless tidal deformabilities are Λ1.4 = 485–626. Furthermore, the direct URCA process in neutron star cooling will happen from n b  = 0.414 to 0.530 fm−3 with the proton fractions Y p  = 0.136–0.138. All of the results obtained from the RBHF model only with two-body pvCD-Bonn potentials completely satisfy various constraints from recent astronomical observations of massive neutron stars, gravitational wave detection (GW170817), and simultaneous mass–radius measurement.