COUNTERROTATING ACCRETION DISKS

Authors: R.V.E. Lovelace and Tom Chou


We consider accretion disks consisting of counterrotating gaseous components with an intervening shear layer. Configurations of this type may arise from the accretion of newly supplied counterrotating gas onto an existing corotating gas disk. For simplicity we consider the case where the gas well above the disk midplane is rotating with angular rate +
W and that well below has the same properties but is rotating with rate -W. Using the Shakura-Sunyaev alpha turbulence model, we find self-similar solutions where a thin (relative to the full disk thickness) equatorial layer accretes very rapidly, essentially at free-fall speed. As a result, the accretion speed is much larger than it would be for an alpha disk rotating in one direction. Counterrotating accretion disks may be a transient stage in the formation of counterrotating galaxies and in the accretion of matter onto compact objects.

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Last updated on 29.01.07