R-modes of neutron stars with a solid crust

Abstract

We investigate the properties of $r$-mode oscillations of a slowly rotating neutron star with a solid crust, by taking account of the effects of the Coriolis force. For the modal analysis we employ three-component neutron star models that are composed of a fluid core, a solid crust and a surface fluid ocean. For the three-component models, we find that there exist two kinds of $r$-modes, that is, those confined in the surface fluid ocean and those confined in the fluid core, which are most important for the $r$-mode instability. The $r$-modes do not have any appreciable amplitudes in the solid crust if rotation rate of the star is sufficiently small. We find that the core $r$-modes are strongly affected by mode coupling with the crustal torsional (toroidal) modes and lose their simple properties of the eigenfunction and eigenfrequency as functions of the angular rotation velocity $\Omega$. This indicates that the extrapolation formula, which is obtained in the limit of $\Omega \to 0$, cannot be used to examine the $r$-mode instability of rapidly rotating neutron stars with a solid crust unless the effects of mode coupling with the crustal torsional modes are correctly taken into account.

10 pages, 3 figures, revised version accepted for publication in the ApJ

References in corpus (8)

• R-Mode Oscillations in Rotating Magnetic Neutron Stars
• R-mode runaway and rapidly rotating neutron stars
• Viscous Boundary Layer Damping of R-Modes in Neutron Stars
• Inertial modes of slowly rotating isentropic stars
• Rotational modes of non-isentropic stars and the gravitational radiation driven instability
• Gravitational-wave driven instability of rotating relativistic stars
• A numerical study of the r-mode instability of rapidly rotating nascent neutron stars
• R-mode oscillations of rapidly rotating Newtonian stars - A new numerical scheme and its application to the spin evolution of neutron stars

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