Neutron star inner crust: effects of rotation and magnetic fields

TL;DR

This paper investigates how pasta phases, magnetic fields, and rotation influence neutron star inner crust properties, with implications for star quakes and crust stability, using relativistic models and self-consistent Einstein-Maxwell solutions.

Contribution

It provides a detailed analysis of the effects of magnetic fields and rotation on neutron star crusts, incorporating pasta phases and different symmetry energy models.

Findings

Models with larger symmetry energy slope are more sensitive to magnetic field variations.

Magnetic and rotational effects can cause Lorentz force maxima and neutral lines inside the crust.

Potential implications for crust fractures and star quake phenomena.

Abstract

We study the role of the pasta phases on the properties of rotating and magnetized neutron stars. In order to investigate such systems, we make use of two different relativistic mean-field unified inner-crust--core equations of state, with a different density dependence of the symmetry energy, and an inner-crust computed within a Thomas-Fermi calculation. Special attention is given to the crust-core transition density, and the pasta phases effects on the global properties of stars. The effects of strong magnetic fields and fast rotation are computed by solving the Einstein-Maxwell equations self-consistently, taking into account anisotropies induced by the centrifugal and the Lorentz force. The location of the magnetic field neutral line and the maximum of the Lorentz force on the equatorial plane are calculated. The conditions under which they fall inside the inner crust region are discussed. We verified that models with a larger symmetry energy slope show more sensitivity to the variation of the magnetic field. One of the maxima of the Lorentz force, as well as the neutral line, and for a certain range of frequencies, fall inside the inner crust region. This may have consequences in the fracture of the crust, and may help explain phenomena associated with star quakes.