Nonequilibrium thermodynamics of accreted neutron-star crust. (arXiv:2109.06614v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Gusakov_M/0/1/0/all/0/1">Mikhail E. Gusakov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kantor_E/0/1/0/all/0/1">Elena M. Kantor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chugunov_A/0/1/0/all/0/1">Andrey I. Chugunov</a>
We show that, in order to determine the equation of state of the inner crust
of an accreting neutron star, one should minimize not the Gibbs free energy, as
it is generally assumed in the literature, but a different thermodynamic
potential $Psi$, which tends to the minimum at fixed pressure and neutron
chemical potential. Once this potential is specified, one can calculate the
heat-release distribution in the stellar crust due to nonequilibrium nuclear
reactions induced by accretion of matter onto the neutron-star surface. The
results are important for adequate modeling of the accreted crust and
interpretation of the observations of accreting neutron stars in low-mass X-ray
binaries.
We show that, in order to determine the equation of state of the inner crust
of an accreting neutron star, one should minimize not the Gibbs free energy, as
it is generally assumed in the literature, but a different thermodynamic
potential $Psi$, which tends to the minimum at fixed pressure and neutron
chemical potential. Once this potential is specified, one can calculate the
heat-release distribution in the stellar crust due to nonequilibrium nuclear
reactions induced by accretion of matter onto the neutron-star surface. The
results are important for adequate modeling of the accreted crust and
interpretation of the observations of accreting neutron stars in low-mass X-ray
binaries.
http://arxiv.org/icons/sfx.gif
