


ID:
379331.0,
MPI für Gravitationsphysik / Observational Relativity and Cosmology 
Slowly rotating superfluid Newtonian neutron star model with entrainment 
Authors:  Prix, Reinhard; Andersson, Nils; Comer, G. L.  Date of Publication (YYYYMMDD):  200201  Title of Journal:  Astronomy and Astrophysics  Volume:  381  Issue / Number:  1  Start Page:  178  End Page:  196  Review Status:  not specified  Audience:  Not Specified  Abstract / Description:  We develop a formalism that can be used to model slowly rotating superfluid Newtonian neutron stars. A simple twofluid model is used to describe the matter, where one fluid consists of the superfluid neutrons that are believed to exist in the inner crust and core of mature neutron stars, while the other fluid is a charge neutral conglomerate of the remaining constituents (crust nuclei, core superconducting protons, electrons, etc.). We include the entrainment effect, which is a nondissipative interaction between the two fluids whereby a momentum induced in one of the fluids will cause part of the mass of the other fluid to be carried along. The equations that describe rotational equilibria (i.e. axisymmetric and stationary configurations) are approximated using the slowrotation approximation; an expansion in terms of the rotation rates of the two fluids where only terms up to secondorder are kept. Our formalism allows the neutrons to rotate at a rate different from that of the charged constituents. For a particular equation of state that is quadratic in the two massdensities and relative velocities of the fluids, we find an analytic solution to the slowrotation equations. This result provides an elegant generalisation to the twofluid problem of the standard expressions for the onefluid polytrope ${\cal E} \propto \rho^2$. The model equation of state includes entrainment and is general enough to allow for realistic values for, say, mass and radius of the star. It also includes a mixed term in the mass densities that can be related to "symmetry energy" terms that appear in more realistic equations of state. We use the analytic solution to explore how relative rotation between the two fluids, the "symmetry energy" term, and entrainment affect the neutron star's local distribution of particles, as well as global quantities as the Kepler limit, ellipticity, and moments of inertia.  External Publication Status:  published  Document Type:  Article 
Communicated by:  Bruce Allen  Affiliations:  MPI für Gravitationsphysik/Teilinstitut Hannover MPI für Gravitationsphysik/Observational Relativity and Cosmology
 Identifiers:  LOCALID:arXiv:astroph/0107176v1 DOI:10.1051/00046361:20011499 ISSN:00046361 URL:http://arxiv.org/abs/astroph/0107176  


The scope and number of records on eDoc is subject
to the collection policies defined by each institute
 see "info" button in the collection browse view.

