Physics input for modelling superfluid neutron stars with hyperon cores

Abstract

Observations of massive (M ≈2.0 M⊙) neutron stars (NSs), PSRs J1614-2230 and J0348+0432, rule out most of the models of nucleon-hyperon matter employed in NS simulations. Here, we construct three possible models of nucleon-hyperon matter consistent with the existence of 2 M⊙ pulsars as well as with semi-empirical nuclear matter parameters at saturation, and semi-empirical hypernuclear data. Our aim is to calculate for these models all the parameters necessary for modelling dynamics of hyperon stars (such as equation of state, adiabatic indices, thermodynamic derivatives, relativistic entrainment matrix, etc.), making them available for a potential user. To this aim a general non-linear hadronic Lagrangian involving σωρφσ* meson fields, as well as quartic terms in vector-meson fields, is considered. A universal scheme for calculation of thel = 0, 1 Landau Fermi-liquid parameters and relativistic entrainment matrix is formulated in the mean-field approximation. Use of this scheme allow us to obtain numerical tables with the equation of state, Landau quasi-particle effective masses, adiabatic indices, the l = 0, 1 Landau Fermi-liquid parameters, and the relativistic entrainment matrix for the selected models of nucleon-hyperon matter. These data are available online and suitable for numerical implementation in computer codes modelling various dynamical processes in NSs, in particular, oscillations of superfluid NSs and their cooling. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.