Protostellar collapse: rotation and disk formation

We present some important conclusions from models of the collapse of rotating molecular cloud cores with axial symmetry, corresponding to the evolution of young stellar objects from class 0 to the beginning class I. There are three main findings of the calculations: (1) typical timescale for building up a preplanetary disk, which was to be of the order of one free-fall time decisively shorter the widely assumed timescale related to the so-called“inside-out collapse”; (2) redistribution of angular momentum and accompanying dissipation of kinetic (rotational) energy causing growing disk to become more stable and strengthening the meridional circulation pattern of the accretion flow; and(3) the origin of calcium-aluminium-rich inclusions (CAIs). Because the persistent equatorial outflow, material that has undergone chemical and mineralogical modifications in the hot(\900 K) interior of the protostellar core may have a good of being advectively transported outward into the cooler parts (\4 AU, say) of the growing disk and surviving until it is incorporated into a meteoritic parent body.