Related papers: Are passive protostellar disks stable to self-shad…
It has been believed that spirals in pure stellar disks, especially the ones spontaneously formed, decay in several galactic rotations due to the increase of stellar velocity dispersions. Therefore, some cooling mechanism, for example…
Turbulence is crucial for protoplanetary disk dynamics, and Vertical Shear Instability (VSI) is a promising mechanism in outer disk regions to generate turbulence. We use Athena++ radiation module to study VSI in full and transition disks,…
A number of previous studies of the fragmentation of self-gravitating protostellar discs have modeled radiative cooling with a cooling timescale (t_{cool}) parameterised as a simple multiple (beta_{cool}) of the local dynamical timescale.…
We study particle dynamics in local two-dimensional simulations of self-gravitating accretion discs with a simple cooling law. It is well known that the structure which arises in the gaseous component of the disc due to a gravitational…
We perform numerical analyses of the structure induced by gravitational instabilities in cooling gaseous accretion discs. For low enough cooling rates a quasi-steady configuration is reached, with the instability saturating at a finite…
When a self-gravitating disc is subject to irradiation, its propensity to fragmentation will be affected. The strength of self-gravitating disc stresses is expected to dictate disc fragmentation: as the strength of these torques typically…
Recent SPH simulations by Martin et al. (2014) suggest a circumstellar gaseous disk may exhibit coherent eccentricity-inclination oscillations due to the tidal forcing of an inclined binary companion, in a manner that resembles Lidov-Kozai…
We present results of numerical N-body simulations of a galactic stellar disk embedded into a spherical dark halo. The non-linear dynamics of bending instabilities developing in the disk is studied. The bending modes, axisymmetric and not,…
We revisit the spectral appearance of extended self-gravitating accretion disks surrounding compact central objects such as supermassive black holes. Using dust-poor opacities, we show that all optically thick disk solutions possess a…
The questions of how strong magnetic fields can be stored in rotating stellar radiative zones without being subjected to pinch-type instabilities and how much radial mixing is produced if the fields are unstable are addressed. Linear…
We present the results of high-resolution, three-dimensional (3D) hydrodynamic simulations of the dynamics and formation of coherent, long-lived vortices in stably-stratified protoplanetary disks. Tall, columnar vortices that extend…
We investigate the stability of black hole accretion disks in a primordial environment (POP III disks for short), by solving the vertical structure of optically thick disks, including convective energy transport, and by employing a one-zone…
The stability of nonaxisymmetric perturbations in differentially rotating astrophysical accretion disks is analyzed by fully incorporating the properties of shear flows. We verify the presence of discrete unstable eigenmodes with complex…
We perform calculations of our one-dimensional, two-zone disk model to study the long-term evolution of the circumstellar disk. In particular, we adopt published photoevaporation prescriptions and examine whether the photoevaporative loss…
We present a linear analysis of the vertical structure and growth of the magnetorotational instability in stratified, weakly ionised accretion discs, such as protostellar and quiescent dwarf novae systems. The method includes the effects of…
A self-gravitating, differentially rotating galactic disc under vertical hydrostatic equilibrium is supported by the vertical pressure gradient force against the gravitational collapse. Such discs are known to support various bending modes…
A detailed solution of an initial value problem of a vertically localized initial perturbation in rotating magnetized vertically stratified disk is presented. The appropriate linearized MHD equations are solved by employing the WKB…
We calculate self-consistent models of X-ray irradiated accretion discs in close binary systems. We show that a point X-ray source powered by accretion and located in the disc plane cannot modify the disc structure, mainly because of the…
Circumstellar asymmetries such as central warps have recently been shown to cast shadows on outer disks. We investigate the hydrodynamical consequences of such variable illumination on the outer regions of a transition disk, and the…
Protoplanetary disks exhibit a vertical gradient in angular momentum, rendering them susceptible to the Vertical Shear Instability (VSI). The most important condition for the onset of this mechanism is a short timescale of thermal…