$Abinitio$ thermodynamics of one-component plasma for astrophysics of white dwarfs and neutron stars

Abstract

Using path-integral Monte Carlo (PIMC) simulations, we have calculated energy of a crystal composed of atomic nuclei and uniform incompressible electron background in the temperature and density range, covering fully ionized layers of compact stellar objects, white dwarfs and neutron stars, including the high-density regime, where ion quantization is important. We have approximated the results by convenient analytic formulae, which allowed us to integrate and differentiate the energy with respect to temperature and density to obtain various thermodynamic functions such as Helmholtz free energy, specific heat, pressure, entropy etc. In particular, we have demonstrated, that the total crystal specific heat can exceed the well-known harmonic lattice contribution by a factor of 1.5 due to anharmonic effects. By combining our results with the PIMC thermodynamics of a quantum Coulomb liquid, updated in the present work, we were able to determine density dependences of such melting parameters as the Coulomb coupling strength at melting, latent heat, and a specific heat jump. Our results are necessary for realistic modelling of thermal evolution of compact degenerate stars.

17 pages, 17 figures, 4 tables, accepted to MNRAS

References in corpus (9)

• The Gaia mission
• ${}^{22}$Ne Phase Separation As A Solution To The Ultramassive White Dwarf Cooling Anomaly
• Phase separation in the crust of accreting neutron stars
• The updated BaSTI stellar evolution models and isochrones. III. White Dwarfs
• Cooling Delays from Iron Sedimentation and Iron Inner Cores in White Dwarfs
• Phase Separation in Ultramassive White Dwarfs
• Structure of Multicomponent Coulomb Crystals
• Quantum ion thermodynamics in liquid interiors of white dwarfs
• Plasma screening of nuclear fusion reactions in liquid layers of compact degenerate stars: a first-principle study

Cited by in corpus (6)

• Modules for Experiments in Stellar Astrophysics (MESA): Time-Dependent Convection, Energy Conservation, Automatic Differentiation, and Infrastructure
• Current challenges in the physics of white dwarf stars
• Phase diagrams of binary ionic mixtures and white dwarf cooling
• On excess entropy and latent heat in crystallizing white dwarfs
• Electrostatic energy of solid binary ionic mixtures
• Constraining shear modulus of polycrystalline neutron star crust: Hashin-Shtrikman variational approach