Related papers: Dwarf Nova Outbursts with Magnetorotational Turbul…
We present a model of an outburst of the soft X-ray transient A0620-003. A two-dimensional time-dependent smoothed particle hydrodynamics scheme is used to simulate the evolution of the accretion disc through a complete outburst. The scheme…
Portions of the Kepler K2 Short Cadence light curve of the dwarf nova (DN) TW Vir at quiescence are investigated using light curve modeling. The light curve was separated into 24 sections, each with a data length of $\sim\,$0.93\,d,…
[Abridged] The turbulent stresses that lead to angular momentum transport in accretion discs have often been treated as resulting from an isotropic effective viscosity, related to the pressure through the alpha parametrization of Shakura &…
Though usually treated in isolation, the magnetorotational and gravitational instabilities (MRI and GI) may coincide at certain radii and evolutionary stages of protoplanetary discs and active galactic nuclei. Their mutual interactions…
Turbulence in the protoplanetary disks induces collisions between dust grains, and thus facilitates grain growth. We investigate the two fundamental assumptions of the turbulence in obtaining grain collisional velocities -- the kinetic…
Previous theoretical studies have found that repeating outbursts can occur in certain regions of an accretion disk, due to sudden transitions in time from gravitationally produced turbulence to magnetically produced turbulence. We analyze…
We present 120s cadence TESS observations of three superoutbursts of the SU UMa-type dwarf nova VW Hydri. Two events (SO2 in Sectors 87+88 and SO3 in Sector 93) exhibit a pronounced, temporally pronounced precursor-dip followed by a rapid…
We study the properties of MHD turbulence driven by the magnetorotational instability (MRI) in accretion disks. We adopt the local shearing box model and focus on the special case for which the initial magnetic flux threading the disk…
We investigate the characteristic properties of self-sustained MRI turbulence in low-ionized proto-planetary disks. We study the transition regime between active and dead-zone, performing 3D global non-ideal MHD simulations of stratified…
Some accreting neutron stars and young stars show unexplained episodic flares in the form of quasi-periodic oscillations or recurrent outbursts. In a series of two papers we present new work on an instability that can lead to episodic…
We show that the Keplerian thin disk in quiescent Soft X-ray Transients cannot extend down to the last stable orbit around the central black hole. We analyse the properties of the Narayan, McClintock & Yi (1996) model of quiescent Soft…
We present the first detailed hydrodynamic simulation of a superoutburst to incorporate the full tidal potential of a binary system. A two-dimensional smoothed particle hydrodynamics code is used to simulate a superoutburst in a binary with…
We study how the magnetorotational instability (MRI) in protoplanetary disks is affected by the electric discharge caused by the electric field in the resistive MHD. We have performed three-dimensional shearing box simulations with various…
A new theory of eccentric accretion discs is presented. Starting from the basic fluid-dynamical equations in three dimensions, I derive the fundamental set of one-dimensional equations that describe how the mass, angular momentum and…
We calculate the effect of illumination of dwarf nova accretion discs by radiation from a hot, central, white dwarf. We show that only for very hot white dwarfs (Teff ~ 40 000$ K) the inner region of quiescent dwarf nova discs are partially…
Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in accretion disks. These disks are thought to be highly…
The self-sustained turbulence which develops in magnetized accretion disks is suppressed in the weakly-ionized, quiescent disks of close binary stars. Because accretion still proceeds during quiescence, another viscosity mechanism operates…
Fluctuations during a prolonged maximum have been observed in several nova eruptions, although it is not clear, and can not be deduced directly from observations, if the phenomenon is an actual physical reaction to some mechanism…
The arising of turbulence in gas-dynamic (non-magnetic) accretion disks is a major issue of modern astrophysics. Such accretion disks should be stable against the turbulence generation, in contradiction to observations. Searching for…
We reanalyse archival GINGA and ASCA X-ray data from SS Cyg in both quiescence and outburst, using multi-temperature plasma models for the continuum and line emission, together with their reflection from the X-ray illuminated white dwarf…