title: Vorticity affects the stability of neutron stars
abstract: The spin rate Omega of neutron stars at a given temperature T is constrained by the interplay between gravitational-radiation instabilities and viscous damping. Navier-Stokes theory has been used to calculate the viscous damping time scales and produce a stability curve for r modes in the (Omega,T) plane. In Navier-Stokes theory, viscosity is independent of vorticity, but kinetic theory predicts a coupling of vorticity to the shear viscosity. We calculate this coupling and show that it can in principle significantly modify the stability diagram at lower temperatures. As a result, colder stars can remain stable at higher spin rates.
authors.affiliation: Relativity and Cosmology Group, Division of Mathematics and Statistics, Portsmouth University, Portsmouth PO1 2EG, United Kingdom and Institute for Advanced Studies in Basic Sciences, Zanjan 45195, Iran.
authors.initials: V
authors.lastname: Rezania
authors.initials: R
authors.lastname: Maartens