Crustal properties of a neutron star within an effective relativistic mean-field model

Abstract

We use the effective relativistic mean-field (E-RMF) model to study the crustal properties of the neutron star. The unified equations of state (EoS) are constructed using recently developed E-RMF parameter sets, such as FSUGarnet, IOPB-I, and G3. The outer crust composition is determined using the atomic mass evaluation 2020 data [Huang et al. Chin. Phys. C 45, 030002 (2021) along with the available Hartree-Fock-Bogoliubov mass models [Goriely et al. Phys. Rev. C 88, 024308 (2013) for neutron-rich nuclei. The structure of the inner crust is estimated by performing the compressible liquid drop model calculations using the same E-RMF functional as that for the uniform nuclear matter in the liquid core. Various neutron star properties such as mass-radius ($M\ensuremath{-}R$) relation, the moment of inertia ($I$), the fractional crustal moment of inertia (${I}_{\text{crust}}/I$), mass (${M}_{\text{crust}}$) and thickness (${l}_{\text{crust}}$) of the crust are calculated with three unified EoSs. The crustal properties are found to be sensitive to the density-dependent symmetry energy and slope parameter advocating the importance of the unified treatment of neutron star EoS. The three unified EoSs, IOPB-I-U, FSUGarnet-U, and G3-U, reproduced the observational data obtained with different pulsars, NICER, and glitch activity and are found suitable for further description of the structure of the neutron star.