Astron. Astrophys. 352, 623-631 (1999)

Slowly rotating two-fluid neutron star model

Reinhard Prix

Département d'Astrophysique Relativiste et de Cosmologie, Centre National de la Recherche Scientifique, Observatoire de Paris, 92195 Meudon, France

Received 7 September 1999 / Accepted 4 November 1999

Abstract

We study stationary axisymmetric configurations of a star model consisting of two barotropic fluids, which are uniformly rotating at two different rotation rates. Analytic approximate solutions in the limit of slow rotation are obtained with the classical method of Chandrasekhar, which consists of an expansion of the solution in terms of the rotation rate, and which is generalized to the case of two fluids in order to apply it to the present problem. This work has a direct application to neutron star models, in which the neutron superfluid can rotate at a different speed than the fluid of charged components. Two cases are considered, the case of two non-interacting fluids, and the case of an interaction of a special type, corresponding to the vortices of the neutron superfluid being completely pinned to the second fluid. The special case of the equation of state is solved explicitly as an illustration of the foregoing results.

Key words: hydrodynamics stars: neutron stars: rotation

Online publication: December 2, 1999

helpdesk@link.springer.de