Supersonic infall and causality in accretion disk boundary layers

Abstract

view Abstract Citations (68) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Supersonic Infall and Causality in Accretion Disk Boundary Layers Popham, Robert ; Narayan, Ramesh Abstract Certain non-physical aspects of the standard alpha-viscosity prescription are identified as the cause of this paradoxical behavior, and a more physically realistic model of viscosity is developed. The viscosity coefficient is modified to account for the reduced radial pressure scale height in the boundary layer. This reduces the radial velocities, but, as noted by previous workers, does not eliminate supersonic infall for large values of alpha. A second factor is included to allow for the fact that the viscosity coefficient must vanish when the steady-state radial velocity of the flow reaches the maximum speed of the diffusive particles that produce the viscosity. When this modification is used, causally connected, physically self-consistent solutions are found for all choices of parameters. It is concluded that information flow between the star and the disk can be maintained in all steady-state accreting systems. Publication: The Astrophysical Journal Pub Date: July 1992 DOI: 10.1086/171577 Bibcode: 1992ApJ...394..255P Keywords: Accretion Disks; Boundary Layers; Stellar Mass Accretion; Supersonic Flow; Computational Astrophysics; Hydrodynamic Equations; Radial Flow; Viscosity; Astrophysics; ACCRETION; ACCRETION DISKS; HYDRODYNAMICS full text sources ADS |