Related papers: R-mode instability in compact stars
We study the viscous damping of r-modes of compact stars and analyze in detail the regions where small amplitude modes are unstable to the emission of gravitational radiation. We present general expressions for the viscous damping times for…
The only r-modes that exist in a globally barotropic, rotating, Newtonian star are the fundamental $l = |m|$ solutions, where $l$ and $m$ are the indices of the spherical harmonic $Y_l^m$ that describe the mode's angular dependence. This is…
We study here the r-modes in the Cowling approximation of a slowly rotating and magnetized neutron star with a poloidal magnetic field, where we neglect any deformations of the spherical symmetry of the star. We were able to quantify the…
In this paper we investigate effects of the $r$-mode instability on a newborn rapidly-rotating magnetar with fall-back accretion. Such a magnetar could usually occur in core-collapse supernovae and gamma-ray bursts. We find that the…
In rotating neutron stars the existence of the Coriolis force allows the presence of the so-called Rossby oscillations (r-modes) which are know to be unstable to emission of gravitational waves. Here, for the first time, we introduce the…
We study the oscillations modes of differential rotating remnants of binary neutron star inspirals by modeling them as incompressible Riemann ellipsoids parametrized by the ratio $f$ of their internal circulation to the rotation frequency.…
At second order in perturbation theory, the $r$-modes of uniformly rotating stars include an axisymmetric part that can be identified with differential rotation of the background star. If one does not include radiation-reaction, the…
R-modes of a rotating neutron star are unstable because of the emission of gravitational radiation. We explore the saturation amplitudes of these modes determined by nonlinear mode-mode coupling. Modelling the star as incompressible allows…
Non radial oscillations of neutron stars are associated with the emission of gravitational waves. The characteristic frequencies of these oscillations can be computed using the theory of stellar perturbations, and they are shown to carry…
We briefly review progress in developing a pathway to nonlinear astereoseismology, both from theoretical and observational aspects. As predicted by the theory of weak nonlinear interactions between resonant modes, their amplitude and…
We consider the spin evolution of highly magnetized neutron stars in a hypercritical inflow just after their birth in supernovae. Presence of a strong magnetic field could deform the star and if the symmetry axis of the field is misaligned…
The evolution of a nonaxisymmetric bar-mode perturbation of rapidly rotating stars due to a secular instability induced by gravitational wave emission is studied in post-Newtonian simulations taking into account gravitational radiation…
In this article we study the possibility that, due to non-linear couplings, unstable g-modes associated to convective motions excite stable oscillating g-modes. This problem is of particular interest, since gravitational waves emitted by a…
We show that r-mode instabilities severely constraint the composition of a compact star rotating at a submillisecond period. In particular, the only viable astrophysical scenario for such an object, present inside the Low Mass X-ray Binary…
We have modelled the nonlinear development of the secular bar-mode instability that is driven by gravitational radiation-reaction (GRR) forces in rotating neutron stars. In the absence of any competing viscous effects, an initially…
We provide a bird's-eye view of neutron-star seismology, which aims to probe the extreme physics associated with these objects, in the context of gravitational-wave astronomy. Focussing on the fundamental mode of oscillation, which is an…
Rotating neutron stars that support long-lived, non-axisymmetric deformations known as mountains have long been considered potential sources of gravitational radiation. However, the amplitude from such a source is very weak and current…
Binary neutron star mergers, such as the multimessenger GW170817 event, may produce hypermassive compact objects which are supported against collapse by the internal circulation of the fluid within the star. We compute their unstable modes…
Asteroseismic inference from pressure modes (p modes) and buoyancy, or gravity, modes (g modes) is ubiquitous for stars across the Hertzsprung--Russell diagram. Until now, however, discussion of r modes (global Rossby waves) has been rare.…
We carry out 3-D numerical simulations of the dynamical instability in rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and 0.5. The calculations are done with a SPH code using Newtonian gravity, and the…