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Equilibrium structure of the outer crust of a cold nonaccreted neutron star

Chamel, Nicolas

This computer code (written in C language) determines the internal constitution of the outer crust of a cold nonaccreted neutron star using the very fast iterative analytical method presented in Phys. Rev. C 101, 032801(R) (2020). An extension to magnetars is available here.

Instead of performing the full numerical minimization of the Gibbs free energy per nucleon for each pressure as in the traditional approach, the sequence of equilibrium nuclei is found by making use of very accurate analytical formulas for the transition pressures between adjacent crustal layers and their density. In addition to the composition of the different crustal layers, their proper depth and their baryonic mass are simultaneously estimated using an approximate solution of Einstein's general relativistic equations.

The code is provided with an example file containing data from the 2016 Atomic Mass Evaluation, measurements of copper isotopes, and from the theoretical nuclear mass model HFB-27.

Usage: ocrust atomic_mass_data_file  [options]

 -e electron exchange not included
 -p electron charge polarizarion not included
 -w Wigner-Seitz approximation
 -t Thomas-Fermi approximation for electron charge polarization.

The format of atomic_mass_data_file should be the following:
     atomic number / mass number / mass excess in MeV

Help: ocrust -h


This work was financially supported by Fonds de la Recherche Scientifique - FNRS (Belgium) under grant No. IISN 4.4502.19
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  • Chamel, Phys. Rev. C 101, 032801(R) (2020)

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