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 [Chinese Physics C {\bf 45}, 030002 (2021)] along with the available Hartree-Fock-Bogoliubov mass models [Phys. Rev. C {\bf 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 ($M-R$) relation, the moment of inertia ($I$), the fractional crustal moment of inertia ($I_{crust}/I$), mass ($M_{crust})$ and thickness ($l_{crust}$) 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.