Related papers: Eccentricity Growth Rates of Tidally Distorted Dis…
It is well established that stellar discs are destabilized by sharp features in their phase space, driving recurrent spiral modes. We explore the extent to which surface-density breaks in disc galaxies - which represent sharp changes in the…
We consider a hierarchical triple system consisting of an inner eccentric binary with an outer companion. A highly misaligned circumbinary disk around the inner binary is subject to two competing effects: (i) nodal precession about the…
In this paper we analyse the propagation of warps in protostellar circumbinary discs. We use these systems as a test environment in which to study warp propagation in the bending-wave regime, with the addition of an external torque due to…
We formulate a local dynamical model of an eccentric disc in which the dominant motion consists of elliptical Keplerian orbits. The model is a generalization of the well known shearing sheet, and is suitable for both analytical and…
We investigate the effects of different dust and gas opacity descriptions on the structure and evolution of the inner regions of protoplanetary discs. The influence on the episodic instability of the inner rim is hereby of central interest.…
We consider the effects of eccentricity on the fragmentation of gravitationally unstable accretion disks, using numerical hydrodynamics. We find that eccentricity does not affect the overall stability of the disk against fragmentation, but…
As of today ten circumbinary planets orbiting solar type main sequence stars have been discovered. Nearly all of them orbit around the central binary very closely to the region of instability where it is difficult to form them in situ. It…
We study radiation-hydrodynamical normal modes of radiation-supported accretion disks in the WKB limit. It has long been known that in the large optical depth limit the standard equilibrium is unstable to convection. We study how the growth…
Many accretion discs have been found to be distorted: either warped due a misalignment in the system, or non-circular as a result of orbital eccentricity or tidal deformation by a binary companion. Warped, eccentric, and tidally distorted…
A new element is proposed to play a role in the evolution of extrasolar planetary systems: the tidal (or elliptical) instability. It comes from a parametric resonance and takes place in any rotating fluid whose streamlines are (even…
We explore test particle orbits in the orbital plane of eccentric stellar binary systems, searching for ``invariant loops'': closed curves that change shape periodically as a function of binary orbital phase as the test particles in them…
Magnetic interactions between a protostar and its accretion disc tend to induce warping in the disc and produce secular changes in the stellar spin direction, so that the spin axis may not always be perpendicular to the disc. This may help…
We study the evolution of the eccentricity of an eccentric orbit with spinning components. We develop a prescription to express the evolving eccentricity in terms of reference eccentricity and frequency. For that purpose we considered the…
We numerically study the precessing disk model for superhump in the SU~UMa subclass of cataclysmic variables, using a two dimensional SPH code specifically designed for thin disk problems. Two disk simulations for a binary with mass ratio…
Recent results by Martin et al. (2014) showed in 3D SPH simulations that tilted discs in binary systems can be unstable to the development of global, damped Kozai-Lidov (KL) oscillations in which the discs exchange tilt for eccentricity. We…
We study precession dynamics of generic binary black holes in eccentric orbits using an effective potential based formalism derived in [M. Kesden et al., PRL {\bf 114}, 081103 (2015)]. This effective potential is used to classify binary…
The standard thin accretion disc model predicts that discs around stellar mass black holes become radiation pressure dominated and thermally unstable once their luminosity exceeds L>0.02 L_Edd. Observationally, discs in the high/soft state…
We consider the dynamics of rotationally supported thin galactic disc composed of stars and gas under the influence of external tidal field and derive the coupled differential equations governing the evolution of instabilities. Further…
Eccentric cavities in circumbinary disks precess on timescales much longer than the binary orbital period. These long-lived steady states can be understood as trapped modes in an effective potential primarily determined by the binary…
Stellar-mass binary black holes may have circumbinary disks if formed through common-envelope evolution or within gaseous environments. Disks can drive binaries into wider and more eccentric orbits, while gravitational waves harden and…