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R. Hueso (Universidad del País Vasco), T. Guillot (Observatoire de la Côte d'Azur)
We present a one-dimensional model of the formation and evolution of protoplanetary disks and we confront it with observational constraints from DM Tau and GM Aur, two classical T-Tauri stars with relatively well characterized disks. The disk early formation is modeled as the result of the gravitational collapse of an isothermal molecular cloud and the disk viscous evolution is integrated according to two parameterizations of turbulence: The classical alpha and a beta parameterization, representative of non-linear turbulence driven by the keplerian shear. We perform a systematic Monte-Carlo exploration of the parameter space (values of the alpha-beta parameters and initial angular momentum of the molecular cloud) to find the values that fit the present disk surface density distribution, star and disk masses, age of the systems and their accretion rates. The large incertitude in the observational data allows only an order of magnitude determination of the key parameters for both systems. We find that DM Tau require viscosities characterized by alpha values of 0.003 < alpha < 0.2 while GM Aur requires 3 times lower viscosities. Both disks are also compatible with viscosities applied under the beta parameterization. We show that the mechanism responsible for turbulent diffusion at large orbital distances most probably cannot be convection because of its suppression at low optical depths.
The author(s) of this abstract have provided an email address for comments about the abstract: wubhualr@lg.ehu.es
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.