Related papers: Precessing warped discs in close binary systems
We study the evolution of circumbinary disks under the gravitational influence of the binary using two-dimensional hydrodynamical simulations to investigate the impact of disk and binary parameters on the dynamical aspects of the disk. To…
The recent discoveries of circumbinary planets by $\it Kepler$ raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary…
The non-axisymmetric structure of accretion disks around the neutron star in Be/X-ray binaries is studied by analyzing the results from three dimensional (3D) Smoothed Particle Hydrodynamics (SPH) simulations. It is found that ram pressure…
Accretion disks in binary systems can exhibit a tilt instability, arising from the interaction between components of the tidal potential and dissipation. Using a linear analysis, we show that the aspect ratios and outer radii of…
Warps are suspected in disks around massive compact objects. However, the proposed warping source -- non-axisymmetric radiation pressure -- does not apply to white dwarfs. In this letter we report the first Smoothed Particle Hydrodynamic…
This dissertation is written as an annotated collection of selected articles. The dissertation focuses on the modelling of accretion disks in X-ray binaries with a black hole or neutron star. The main objective is to use advanced numerical…
Young multiple systems accrete most of their final mass in the first few Myr of their lifetime, during the protostellar and protoplanetary phases. Previous studies showed that in binary systems the majority of the accreted mass falls onto…
Speckle interferometry of the young binary system RW Aur was performed with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences using filters with central wavelengths of 550 nm and 800 nm and…
We present the evolution of rotational directions of circumstellar disks in a triple protostar system simulated from a turbulent molecular cloud core with no magnetic field. We find a new formation pathway of a counter-rotating…
X-ray luminosities of accreting T Tauri stars are observed to be systematically lower than those of non-accretors. There is as yet no widely accepted physical explanation for this effect, though it has been suggested that accretion somehow…
Millisecond x-ray pulsars have weak magnetic dipole moments of $\sim 10^{16}$\,T\,m$^3$ compared to ordinary X-ray pulsars with dipole moments of $10^{20}$\,T\,m$^3$. For this reason a surrounding accretion disc can extend closer to the…
When an accretion disk surrounds a binary rotating in the same sense, the binary exerts strong torques on the gas. Analytic work in the 1D approximation indicated that these torques sharply diminish or even eliminate accretion from the disk…
We model the overall shape of an accretion disc in a semi-detached binary system in which mass is transfered on to a spinning black hole the spin axis of which is misaligned with the orbital rotation axis. We assume the disc is in a steady…
In the last decade multi-wavelength observations have demonstrated the importance of jets in the energy output of accreting black hole binaries. The observed correlations between the presence of a jet and the state of the accretion flow…
We study a warping instability of a geometrically thin, non-self-gravitating, circumbinary disk around young binary stars on an eccentric orbit. Such a disk is subject to both the tidal torques due to a time-dependent binary potential and…
The question whether the interaction of a circumbinary disc with the central binary system leads to shrinking or expansion of the binary orbit has attracted considerable interest as it impacts the evolution of binary black holes and stellar…
Be stars are surrounded by outflowing circumstellar matter structured in the form of decretion discs. They are often members of binary systems, where it is expected that the decretion disc interacts both radiatively and gravitationally with…
Although during the last decade new observations and new theoretical results have brought better understanding of the physics of accretion onto compact objects, many old and several new questions and problems await answers and solutions. I…
Astrophysical discs are often warped, that is, their orbital planes change with radius. This occurs whenever there is a non-axisymmetric force acting on the disc, for example the Lense-Thirring precession induced by a misaligned spinning…
Accretion discs are present around both stellar-mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei. A wide variety of circumstantial evidence implies that many of these discs are warped. The standard…