Effect of quantizing magnetic field on the inner crusts of hot Neutron Stars

TL;DR

This study investigates how strong magnetic fields and finite temperature influence the structure and properties of the inner crust of hot neutron stars, revealing magnetic field effects on nuclear composition and crust size.

Contribution

It provides a detailed analysis of the combined effects of magnetic fields and temperature on neutron star crusts using Skyrme models and the WS approximation, highlighting new insights into crust composition.

Findings

Magnetic fields reduce the size of the crustal cells.

Magnetic fields increase the nucleon number within nuclei.

Finite temperature diminishes magnetic field effects on crust properties.

Abstract

In the present work we study the effects of strongly quantizing magnetic fields and finite temperature on the properties of inner crusts of hot neutron stars. The inner crust of a neutron star contains neutron-rich nuclei arranged in a lattice and embedded in gases of free neutrons and electrons. We describe the system within the Wigner-Seitz (WS) cell approximation. The nuclear energy is calculated using Skyrme model with SkM* interaction. To isolate the properties of nuclei we follow the subtraction procedure presented by Bonche, Levit and Vautherin, within the Thomas-Fermi approximation. We obtain the equilibrium properties of inner crust for various density, temperatures and magnetic fields by minimizing the free energy of the WS cell satisfying the charge neutrality and $\beta-$equilibrium conditions. We infer that at a fixed baryon density and temperature, strong quantizing magnetic field reduces the cell radii, neutron and proton numbers in the cell compared with the field free case. However, the nucleon number in the nucleus increases in presence of magnetic field. The free energy per nucleon also decreases in magnetized inner crust. On the other hand, we find that finite temperature tends to smear out the effects of magnetic field. Our results can be important in the context of $r-$process nucleosynthesis in the binary neutron star mergers.