During the past decade it has been recognized that young stellar objects and symbiotic stellar systems (usually binary systems) accrete matter from circumstellar accretion disks. Torbett proposes to study this accretion and the bi-polar outflow of matter that is observed from these objects. His numerical modelling is based on the hypothesis that matter arriving at the star's surface from the disk creates a shock, gives up its rotational kinetic energy, heats the local matter, creates high pressures, and accelerates this matter along the two polar directions. (Acceleration in the radial direction is prevented by the arrival of new material from the disk.) This theoretical investigation will be accompanied by VLA radio observation of objects with bipolar flows.
