Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1H005

NECESSARY CONDITION FOR CIRCUMSTELLAR DISK FORMATION

Machida, Masahiro (Kyushu University)

Abstract:
The formation of the circumstellar disk in collapsing cloud cores is investigated with three-dimensional magnetohydrodynamic simulations. We prepare four types of initial cloud having different density profiles, and calculate their evolution with or without sink. To investigate the effect of magnetic dissipation on the disk formation, the Ohmic dissipation is considered in some models. Calculations show that the disk formation is very sensitive to both the initial cloud configuration and sink treatment. The disk size differs considerably in clouds with different density profiles even when the initial clouds have almost the same mass-to-flux ratio. Only a very small disk appears in clouds with uniform density profile, while a large disk with a size forms in clouds with Bonnor-Ebert density profile. In addition, a large sink accretion radius numerically impedes the disk formation during the main accretion phase. The protostellar outflow is also greatly affected by sink properties. The sink accretion radius of less than 1 AU and sink threshold density of higher than 10^13cm^|3 are necessary to investigate the disk formation during the main accretion phase

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