Disc breaking and parametric instability in warped accretion discs

Abstract

We present the first local simulations of disc breaking/tearing in a warped accretion disc. Warps can arise due to a misalignment between the disc and the rotation axis of the central object, or a misalignment with the orbital plane of a binary (or planetary) companion. Warped discs can break into rings, as found in observations of circumbinary protoplanetary discs and global simulations of tilted discs around spinning black holes. In this work we isolate the mechanism of disc breaking in high-resolution, quasi-2D, local (shearing box), hydrodynamic simulations of a Keplerian disc. We consider the evolution of a free (unforced) warp in the wavelike ($\alpha <H/r$) regime. At large warp amplitudes (${\psi }_{\text{max}}\gtrsim 1$) the disc breaks into four rings on timescales of around 20 orbits which are separated by gaps of around $\sim 10H_0$. The warp exhibits a rich tapestry of small-scale dynamics, including horizontal sloshing motions, vertical oscillations or bouncing, warp steepening, and shocks. The shocks act as a source of enhanced dissipation which facilitates gap opening and thus disc breaking. At smaller warp amplitudes ${\psi }_{\text{max}}\lesssim 1$, for which we also develop a quasi-linear theory, the disc does not break, but instead exhibits hydrodynamic parametric instability. We also investigate the effect of viscosity: at small warp amplitudes the parametric instability is damped and the warp propagates as a pure bending wave, while at large warp amplitudes the emerging gaps are partially filled by viscous diffusion.

22 pages, 15 figures, 1 table, submitted to MNRAS

References in corpus (40)

• PLUTO: a Numerical Code for Computational Astrophysics
• Shadows cast by a warp in the HD 142527 protoplanetary disk
• Tearing up the disc: misaligned accretion on to a binary
• On the diffusive propagation of warps in thin accretion discs
• On the tilting of protostellar disks by resonant tidal effects
• Wave-like warp propagation in circumbinary discs I. Analytic theory and numerical simulations
• On the Bardeen-Petterson Effect in black hole accretion discs
• Tearing up the disc: how black holes accrete
• Hydrodynamic Simulations of the Bardeen-Petterson Effect
• The evolution of misaligned accretion discs and spinning black holes
• Signatures of broken protoplanetary discs in scattered light and in sub-millimetre observations
• Disc Tearing and Bardeen-Petterson Alignment in GRMHD Simulations of Highly Tilted Thin Accretion Discs
• A triple star system with a misaligned and warped circumstellar disk shaped by disk tearing
• Inclined Massive Planets in a Protoplanetary Disc: Gap Opening, Disc Breaking, and Observational Signatures
• A conservative orbital advection scheme for simulations of magnetized shear flows with the PLUTO code
• Tearing up a misaligned accretion disc with a binary companion
• Broken discs: warp propagation in accretion discs
• Evolution of warped and twisted accretion discs in close binary systems
• Linear Analysis of the Evolution of Nearly Polar Low Mass Circumbinary Discs
• Shadowing and multiple rings in the protoplanetary disk of HD 139614
• Local and global dynamics of warped astrophysical discs
• Wave-like warp propagation in circumbinary discs II. Application to KH 15D
• Linear and non-linear theory of a parametric instability of hydrodynamic warps in Keplerian discs
• Hydrodynamic Simulations of Propagating Warps and Bending Waves In Accretion Discs
• An alpha theory of time-dependent warped accretion discs
• Nonlinear bending waves in Keplerian accretion discs
• Instability of warped discs
• Disc tearing: numerical investigation of warped disc instability
• Nozzle Shocks, Disk Tearing and Streamers Drive Rapid Accretion in 3D GRMHD Simulations of Warped Thin Disks
• Disk Tearing Leads to Low and High Frequency Quasi Periodic Oscillations in a GRMHD Simulation of a Thin Accretion Disk
• Warp propagation in astrophysical discs
• Apsidal precession, disc breaking and viscosity in warped discs
• Rocking shadows in broken circumbinary discs
• The Bardeen-Petterson effect in accreting supermassive black-hole binaries: disc breaking and critical obliquity
• On the dynamics of low-viscosity warped discs around black holes
• On the equations of warped disc dynamics
• Local numerical simulations of warped discs
• Hydrodynamic convection in accretion discs
• Millimeter Observations of the disk around GW Ori
• Hydrodynamics of warps in the local model of astrophysical discs

Cited by in corpus (1)

• Warps survive beyond fly-by encounters in protoplanetary disks. RW Aur A as a case study