Related papers: Ekman Pumping in Compact Astrophysical Bodies
We consider how superfluidity of dripped neutrons in the crust of a neutron star affects the frequencies of the crust's fundamental torsional oscillations. A nonnegligible superfluid part of dripped neutrons, which do not comove with…
We review selected aspects of the interior physics of compact stars, focusing on the microscopic and macroscopic manifestations of spin, magnetic fields, and nucleonic superfluidity and superconductivity. Spin statistics of fermions allows…
We perform one of the first studies into the nonlinear evolution of tidally excited inertial waves in a uniformly rotating fluid body, exploring a simplified model of the fluid envelope of a planet (or the convective envelope of a…
Pulsars show a steady decrease in their rotational frequency, occasionally interrupted by sudden spin-ups called glitches, whose physical origin is still a mystery. One suggested explanation for at least the small glitches are starquakes,…
Neutron stars are supposed to be mainly formed by a neutron superfluid. The angular momentum is given by the vortex array within the fluid, and a good account of the observable effects is determined by its coupling with the crust. In this…
We present some results about a novel damping mechanism of r-mode oscillations in neutron stars due to processes that change the number of protons, neutrons and electrons. Deviations from equilibrium of the number densities of the various…
Glitches are sudden spin-up events that interrupt the gradual spin-down of rotating neutron stars. They are believed to arise from the rapid unpinning of vortices in the neutron star inner crust. The analogy between the inner crust of…
Using numerical simulations based on solving the general relativistic hydrodynamic equations, we study the dynamics of a phase transition in the dense core of isolated rotating neutron stars, triggered by the back bending instability…
Context: The observations of rapidly rotating stars are increasingly detailed and precise thanks to interferometry and asteroseismology; two-dimensional models taking into account the hydrodynamics of these stars are very much needed. Aims:…
Using time evolutions of the relevant linearised equations we study non-axisymmetric oscillations of rapidly rotating and superfluid neutron stars. We consider perturbations of Newtonian axisymmetric background configurations and account…
Waves in thin fluid layers are important in various stellar and planetary problems. Due to rapid rotation such systems will become oblate, with a latitudinal variation in the gravitational acceleration across the surface of the object. In…
We model a rotating star as a compressible fluid subject to gravitational forces. In almost all the mathematical literature the entropy is considered to be constant. Here we allow it to be variable. We consider a star that steadily rotates…
The settling dynamics of spherical and elliptical particles in a viscous Newtonian fluid are investigated numerically using a finite difference technique. The terminal velocity for spherical particles is calculated for different system…
The assumption of asymptotic flatness for isolated astrophysical bodies may be considered an approximation when one considers a cosmological context where a cosmological constant or vacuum energy is present. In this framework we study the…
Depending on mass and rotational frequency, gravity compresses the matter in the core regions of neutron stars to densities that are several times higher than the density of ordinary atomic nuclei. At such huge densities atoms themselves…
Disk accretion onto a slowly rotating neutron star with a weak magnetic field $H < 3\times 10^8$ gauss is considered in a wide range of luminosities $1/100 < L/L_{edd} < 1,$ where $L_{edd}$ is the Eddington luminosity. We construct a theory…
Neutron stars are not observed to spin faster than about half their breakup rate. This limiting rotational frequency may be related to the strength of their crusts. As a star spins up from accretion, centrifugal forces stress the crust. We…
We show that the inclusion of simple anisotropic pressures stops the isotropic Friedmann universe being a stable attractor as an initial or final singularity is approached when pressures can exceed the energy density. This shows that the…
We use time-evolutions of the linear perturbation equations to study the oscillations of rapidly rotating neutrons stars. Our models account for the buoyancy due to composition gradients and we study, for the first time, the nature of the…
As rotating neutron stars slow down, the pressure and the density in the core region increase due to the decreasing centrifugal forces and phase transitions may occur in the center. We extract the analytic behavior near the critical angular…