The Rise and Fall of α-Model Viscosity

  • F. V. Hessman
  • C. Obach
Conference paper
Part of the Astrophysics and Space Science Library book series (ASSL, volume 208)


For nearly two decades, our only useful model for the viscosity in accretion disks has been the so-called ‘α-model’. However, it has become clear that the simplest models — in which α is constant — are inadequate to explain the range of behaviours seen in real disks. We show that the properties of steady-state, vertically-averaged models can be determined without any assumptions other than that the disks obey the classical Navier-Stokes equation. These solutions have derived values of α which vary with radius by many orders of magnitude even in small CV disks.


Accretion Disk Accretion Rate Cataclysmic Variable Outer Disk Symbiotic Star 
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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • F. V. Hessman
    • 1
  • C. Obach
    • 1
  1. 1.Universitäts-Sternwarte GöttingenGermany

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