Properties of the outer crust of strongly magnetized neutron stars from Hartree-Fock-Bogoliubov atomic mass models

Abstract

The equilibrium properties of the outer crust of cold nonaccreting magnetars (i.e. neutron stars endowed with very strong magnetic fields) are studied using the latest experimental atomic mass data complemented with a microscopic atomic mass model based on the Hartree-Fock-Bogoliubov method. The Landau quantization of electron motion caused by the strong magnetic field is found to have a significant impact on the composition and the equation of state of crustal matter. It is also shown that the outer crust of magnetars could be much more massive than that of ordinary neutron stars.

Effect of strong magnetic fields on the crust-core transition and inner crust of neutron stars

“…However, in Refs. [32,33], the non-negligible effect of the magnetic field on the properties of the outer crust has already been discussed. Even though the largest fields detected on the surface of magnetars are 2 × 10 15 G on the SGR 180620 (see, e.g., Ref.…”

“…The effect of the magnetic field on the outer crust was analyzed in Ref. [32], within a Hartree-Fock-Bogoliubov calculation, and it was shown that the Landau quantization of the electron motion could affect the outer crust equation of state, giving rise to more massive outer crusts than the expected in usual neutron stars. Also, the neutron drip density and pressure are affected by a strong magnetic field, showing typical quantum oscillations, which shift the transition outer-inner crust to larger or smaller densities [33], according to the field intensity.…”

Constraints on the equation of state of cold dense matter from nuclear physics and astrophysics

“…[3] for details). The properties of the outer crust in the presence of a strong magnetic field were also studied [18]. For the inner crust, we used the temperature-dependent Thomas-Fermi method extended up to the 4th order, with proton shell corrections added via the Strutinsky integral theorem.…”

Neutron star properties with unified equations of state of dense matter

“…For these reasons, we have recently developed a family of three different unified EoSs reflecting the current lack of knowledge of high-density matter Pearson et al 2011Pearson et al , 2012Chamel et al 2012). Our EoSs are based on the nuclear energy density functional (EDF) theory, which has proved to be very successful for describing the properties of medium-mass and heavy nuclei Stone & Reinhard 2007).…”