Accretion Disk Evolution
نویسندگان
چکیده
منابع مشابه
Accretion Disk Evolution With Wind Infall I
The evolution of an accretion disk can be innuenced signiicantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass innux impacts the long-term behavior of the disk by providing additional sources of viscosity and heating. In this paper, we derive and solve the disk equations when these eeects are taken into account. We present a survey of models with v...
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We consider the classic MHD turbulent dynamo operating in a thin, Keplerian accretion disk powered by turbulent viscous stress. The character of the turbulence is encapsulated into two constant parameters: the Shakura-Sunyaev dimensionless viscosity, SS , and the Coriolis number, = 2 corr. The dependence of the total electromotive force on SS and is derived and the dynamo-generated magnetic eld...
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Dynamos in astrophysical disks are usually explained in terms of the standard alpha-omega mean field dynamo model where the local helicity generates a radial field component from an azimuthal field. The subsequent shearing of the radial field gives rise to exponentially growing dynamo modes. There are several problems with this model. The exponentiation time for the galactic dynamo is hard to c...
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It is suggested that tidal interaction of an accreting planetary embryo with the gaseous pre-planetary disk may provide a mechanism to breach the so-called runway limit during the formation of the giant planet cores. The disk tidal torque converts a would-be shepherding obj ect into a “predator”, which can continue to cannibalize the planet.esirnal disk. This is more likely to occur in the gian...
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The nature of AXPs/SGRs (anomalous X-ray pulsars/soft γ-ray repeaters) and high field radio pulsars is still unclear even in the magnetar and/or accretion models. The detection of radio emission from AXP XTE J1810−197 and the discovery of a debris disk around AXP 4U 0142+61 might shed light on the problem. We propose that AXPs/SGRs could be pulsars that have magnetic field B 10 13 G as normal p...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1987
ISSN: 0252-9211
DOI: 10.1017/s0252921100105007