Unified equation of state for the outer and inner crusts of magnetars

Y D Mutafchieva,J M Pearson,L M Mihailov,N Chamel,Zh K Stoyanov

doi:10.1088/1742-6596/1555/1/012015

Abstract

Magnetars form a subclass of neutron stars characterized by magnetic fields of order 1014 − 1015 G at their surface. According to numerical simulations, the magnetic fields in their interior could potentially be even stronger. Such magnetic fields are so extreme that the internal constitution of neutron stars may be altered. The effects of Landau-Rabi quantisation of electron motion on the equation of state and on the equilibrium composition of the crust of a neutron star are investigated for a wide range of magnetic field strengths. Both the outer and inner parts of the crust are treated in a unified and consistent way within the nuclear-energy density functional theory.

Highlights

The effects of Landau-Rabi quantisation of electron motion on the equation of state and on the equilibrium composition of the crust of a neutron star are investigated for a wide range of magnetic field strengths
Whereas most pulsars are endowed with magnetic fields of order 1012 G, some neutron stars may be formed with extremely high magnetic fields of order 1014 − 1015 G, as first proposed by Thompson and Duncan [1]
We have recently shown that the equilibrium properties of the outer and inner crusts of a neutron star could be altered if the magnetic field is strong enough due to Landau-Rabi quantisation of electron motion [8,9,10,11]

Summary

Introduction

Whereas most pulsars are endowed with magnetic fields of order 1012 G, some neutron stars may be formed with extremely high magnetic fields of order 1014 − 1015 G, as first proposed by Thompson and Duncan [1]. According to numerical simulations [2,3,4,5,6], the internal magnetic fields can reach ∼ 1018 G. The existence of such highly magnetised neutron stars so-called magnetars has been confirmed by various astrophysical observations We have recently shown that the equilibrium properties of the outer and inner crusts of a neutron star could be altered if the magnetic field is strong enough due to Landau-Rabi quantisation of electron motion [8,9,10,11]. We present new results for intermediate magnetic field strengths

Outer crust

Conclusion