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S. S. Davis (NASA Ames Research Center)
The dynamical evolution of a thin-disk nebula is an important component of current investigations into chemical and material migration in the protoplanetary nebula. A simple formulation using a hydrodynamic turbulent viscosity model can account for density and temperature evolution over the viscous accretion portion of the disk’s lifetime. The model is based on an analytical solution of the nebula evolution equation and captures major properties of the disk. In particular, the evolving separation between inward and outward accretion and the time-dependent temperature field is predicted using simple formulas. The analytical formulas are compared with available numerical solutions based on the well known alpha-viscosity model.
The model presented is related to a functional analytical model (Cassen, 1994) and to a number of models based on a hydrodynamic source of shear-layer turbulence. The latter model, heretofore used for steady-state disks, is shown to be a useful tool for disk evolution studies.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.