Analytical determination of the structure of the outer crust of a cold nonaccreted neutron star

Abstract

A very fast iterative method is presented to calculate the internal constitution of the outer crust of a cold nonaccreted neutron star, 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 depth and their baryonic mass content can be simultaneously estimated using an approximate solution of Einstein's general relativistic equations. The overall computing time is drastically reduced compared to the traditional approach, thus opening the door to large-scale statistical studies and sensitivity analyses.

The origin of the elements and other implications of gravitational wave detection for nuclear physics

“…This binding energy per nucleon is relatively constant and gave a first clue for the short-range nature of the nuclear interaction. The peak near the region of 56 Fe strongly correlates with the abundance peak of the well-bound iron-group elements.…”

“…Ruester et al [52], Roca-Maza and Piekarewicz [53], and Kreim et al [54] have also pursued such work, studying the impact of a wider range of mass models, while Utama et al [55] have done so using a Bayesian neural network approach. Chamel [56] has now greatly improved the speed of such calculations by avoiding a full minimization of the Gibbs free energy, which allows more systematic study and better determination of the abundances in the thinner but deeper layers of the star. Also discussed in [56] is the treatment of the inner crust, which is important for modeling the ejection of r process nuclides from neutronstar mergers.…”

“…Chamel [56] has now greatly improved the speed of such calculations by avoiding a full minimization of the Gibbs free energy, which allows more systematic study and better determination of the abundances in the thinner but deeper layers of the star. Also discussed in [56] is the treatment of the inner crust, which is important for modeling the ejection of r process nuclides from neutronstar mergers.…”

Anisotropic neutron stars with hyperons: implication of the recent nuclear matter data and observations of neutron stars

“…[112] while the new analytical determination of the structure of the outer crust of a cold nonaccreted neutron star can be found in Ref. [113]. The inner crust EOS is less certain than the outer crust EOS.…”

A New Mass Model for Nuclear Astrophysics: Crossing 200 keV Accuracy

“…As discussed in Refs. [4,5], at β-equilibrium, the composition of each layer of the crust at a given pressure P is obtained by minimising the Gibbs free energy per nucleon. The latter is the sum of three main contributions: the nuclear, electronic, and lattice.…”