The structure and kinematics of bipolar outflows - Observations and models of the Monoceros R2 outflow

An effort is described to model detailed CO observations of the spatially well-resolved and highly collimated bipolar outflow associated with Mon R2. The models indicate that the extent to which the outflows appear bipolar on the sky depends predominantly on the structure of the velocity field of the outflowing gas. Two of the outflow lobes are very well fitted by a paraboloidal shell model. The model which best fits the velocity structure of the outflow is one whose velocity field is characterized by a velocity power law in which v is proportional to R. Velocity sorting of initially clumpy flow gas due to entrainment by a wind or perhaps an explosion probably gives rise to the observed power law.