Accretion Disks and Bipolar Outflows

In the final stages of protostar collapse, we may expect that because of conservation of angular momentum the matter from the nebula will continue to accrete onto the star from an equatorial accretion disk. There is also strong empirical evidence that young stars produce very strong stellar winds that are focused perpendicular to the equatorial accretion disk. Thus, accretion disks and strong bipolar outflow may be a rather common feature of stars collapsing to the main sequence. The adjacent figure illustrates, as does this animation.