On the energy dissipation rate at the inner edge of circumbinary discs

Abstract

We study, by means of numerical simulations and analysis, the details of the accretion process from a disc onto a binary system. We show that energy is dissipated at the edge of a circumbinary disc and this is associated with the tidal torque that maintains the cavity: angular momentum is transferred from the binary to the disc through the action of compressional shocks and viscous friction. These shocks can be viewed as being produced by fluid elements which drift into the cavity and, before being accreted, are accelerated onto trajectories that send them back to impact the disc. The rate of energy dissipation is approximately equal to the product of potential energy per unit mass at the disc's inner edge and the accretion rate, estimated from the disc parameters just beyond the cavity edge, that would occur without the binary. For very thin discs, the actual accretion rate onto the binary may be significantly less. We calculate the energy emitted by a circumbinary disc taking into account energy dissipation at the inner edge and also irradiation arising there from reprocessing of light from the stars. We find that, for tight PMS binaries, the SED is dominated by emission from the inner edge at wavelengths between 1-4 and 10 $\mu$m. This may apply to systems like CoRoT 223992193 and V1481 Ori.

14 pages, 11 figures, accepted for publication in MNRAS

References in corpus (6)

• Three Dimensional MHD Simulation of Circumbinary Accretion Disks -2. Net Accretion Rate
• Direct Imaging of Bridged Twin Protoplanetary Disks in a Young Multiple Star
• Periodic accretion from a circumbinary disk in the young binary UZ Tau E
• Anomalous Accretion Activity and the Spotted Nature of the DQ Tau Binary System
• Interferometric Evidence for Resolved Warm Dust in the DQ Tau System
• Structures in circumbinary disks: Prospects for observability

Cited by in corpus (5)

• Binary black hole mergers in AGN accretion discs: gravitational wave rate density estimates
• Evolution of binary black holes in AGN accretion discs: Disc-binary interaction and gravitational wave emission
• CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk
• Exploiting periodic orbits as dynamical clues for Kepler and K2 systems
• Evolution of circumbinary accretion disk around supermassive binary black hole: post-Newtonian hydrodynamics versus Newtonian hydrodynamics