Related papers: Retrograde Polish Doughnuts around Boson Stars
Exact models of uniformly rotating strange stars, built of self bound quark matter, are calculated within the framework of general relativity. This is made possible thanks to a new numerical technique capable to handle the strong density…
Strangeon stars, which are proposed to describe the nature of pulsar-like compact stars, have passed various observational tests. The maximum mass of a non-rotating strangeon star could be high, which implies that the remnants of binary…
We study in detail the structure of phase space in the neighborhood of stable periodic orbits in a rotating 3D potential of galactic type. We have used the color and rotation method to investigate the properties of the invariant tori in the…
A common point of view is that stable polar structures are mainly present in the E/S0 early-type galaxies lacking dense gas in their host disks. However, nuclear, as well as external polar rings and disks also exist in the late-type hosts,…
This is the second of a series of papers investigating the oscillation properties of relativistic, non-selfgravitating tori orbiting around black holes. Extending the work done in a Schwarzschild background, we here consider the…
The confinement of liquid crystals inside curved geometries leads to exotic structures, with applications ranging from bio-sensors to optical switches and privacy windows. Here we study how curvature affects the alignment of a cholesteric…
We analyze the stability of relativistic, quasi-equilibrium binary neutron stars in synchronous circular orbit. We explore stability against radial collapse to black holes prior to merger, and against orbital plunge. We apply theorems based…
The merger remnant of a binary neutron star coalescence is initially strongly differentially rotating. Some properties of these remnants can be accurately modeled through building equilibrium neutron star models. In the present paper, we…
Models of differentially rotating protoneutron stars are calculated, using realistic equations of state of dense hot matter. Various conditions within the stellar interior, corresponding to different stages of protoneutron star evolution,…
We construct axially symmetric, rotating boson stars with positive and negative parity. Their flat space limits represent spinning Q-balls. $Q$-balls and boson stars exist only in a limited frequency range. The coupling to gravity gives…
Motivated by recent developments in the realm of matter waves, we explore the potential of creating solitary waves on the surface of a torus. This is an intriguing perspective due to the role of curvature in the shape and dynamics of the…
We further investigate the runaway instability of relativistic tori around black holes assuming a power law distribution of the specific angular momentum. We neglect the self-gravity of the torus; thus the gravitational field of the system…
We derive the bulk viscous time scale of neutron stars with quark matter core, i.e. hybrid stars. The r-mode instability windows of the stars show the theoretical result accords with the rapid rotation pulsar data. The fit gives a strong…
The effects of rapid rotation on stellar evolution can be profound. We are now beginning to gather enough data to allow a realistic comparison between different physical models. Two key tests for any theory of stellar rotation are first…
We consider collective dynamics of self-propelling particles in two dimensions. They can align themselves according to the direction of propulsion of their neighbours, together with a random perturbation (i.e. rotational fluctuation). They…
Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central engine. The compact sizes (only a few pc) determined in recent high-resolution observations require that the obscuring matter be clumpy and…
Toroidal pulses, also known as Focused or Flying Doughnuts (FDs), are few-cycle pulses of doughnut-like topology. Originally proposed by Hellwarth and Nouchi in 1996, they have recently been experimentally realized. Toroidal pulses exhibit…
In this paper, all possible orbits of test particles are investigated by using phase plane method in regular Hayward black hole space-time. Our results show that the time-like orbits are divided into four types: unstable circular orbits,…
Both the core collapse of rotating massive stars, and the coalescence of neutron star (NS) binaries, result in the formation of a hot, differentially rotating NS remnant. The timescales over which differential rotation is removed by…
We report an unexpected reverse spiral turn in the final stage of the motion of rolling rings. It is well known that spinning disks rotate in the same direction of their initial spin until they stop. While a spinning ring starts its motion…