Structure and appearance of winds from supercritical accretion disks. I. Numerical models

Journal Article · Mon Oct 15 04:00:00 EDT 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157428· OSTI ID:5729245

Meier, D L

This is the first of two papers that investigate models of radiation-driven winds from super-critical accretion disks. The main assumptions in the models are that the mass and luminosity in the wind emanate from the radius in the disk where accretion becomes supercritical (the critical radius) and that the wind is spherical. In this first paper the equations for disk and wind structure are derived and a steady-state hydrodynamic computer code is develoved and used to solve these equations with the same relaxation techniques used in stellar structure problems. The second paper derives analytic approximations to the results and applies them to various astrophysical systems. The models have four parameters; the mass of the accreting star M, the total accretion rate M/sub T/, ..cap alpha..' (a generalized form of the original disk ..cap alpha.. parameter including heating by processes other than viscosity), and the ratio of the total luminosity to the Eddington luminosity GAMMA/sub T/.For accretion onto a hard-surfaced star, steady, optically thick winds result for even slightly supercritical accretion. The photosphere is typically approx.10/sup 3/ times the critical radius, hiding much or all of the disk and in some cases a binary companion as well. The object will appear as a supergiant star with a high mass loss rate and a non-blackbody spectrum. Transition from subcritical to supercritical accretion is expected to be a dynamical event, but eventually a stable wind should obtain even if ejection from an unstable disk occurs intermittently. Winds from black hole accretion disks may be somewhat different, but the differences will depend on the form of accretion interior to the critical radius. The nature of these wind indicates they should be applicable to a wide variety of accretion phenomena including cataclysmic and X-ray binaries and perhaps quasars.

• Research Organization: Department of Astronomy, The University of Texas at Austin
• OSTI ID: 5729245
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 233:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BLACK HOLES
CONVECTION
FLUID FLOW
FLUID MECHANICS
GIANT STARS
HYDRODYNAMICS
LUMINOSITY
MATHEMATICAL MODELS
MATHEMATICS
MECHANICS
NUMERICAL ANALYSIS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION TRANSPORT
STABILITY
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STARS
STEADY-STATE CONDITIONS
STELLAR WINDS
SUPERGIANT STARS
TURBULENT FLOW