Crust-cooling Models Are Insensitive to the Crust-Core Transition Pressure for Realistic Equations of State

Neutron stars cooling after sustained accretion outbursts provide unique information about the neutron star crust and underlying dense matter. Comparisons between astronomical observations of these cooling transients and model calculations of neutron star crust cooling have frequently been used to constrain neutron star properties such as the mass, radius, crust composition, and presence of nuclear pasta. These calculations often use a fixed pressure at which the crust-core transition happens, though this quantity depends on the dense matter equation of state. We demonstrate that varying the crust-core transition pressure in a manner consistent with adopting various equations of state results in modest changes to the crust-cooling light curve. This validates the approach adopted in most crust-cooling studies to date, where the neutron star mass and radius are varied while leaving the crust-core transition pressure constant.