THE BLUE-BULGE INFALL SIGNATURE TOWARD IRAS-16293-2422

We present the first detection of the ''blue-bulge'' infall signature toward a protostellar source. The blue-bulge infall signature can be o bserved in the centroid velocity maps of protostellar objects when inf all dominates over rotation. This infall signature can be detected und er a wide variety of source conditions. The detection of the blue-bulg e infall signature toward a protobinary system such as IRAS 16293 - 24 22 suggests that detailed studies of gravitational collapse toward a l arge number of protostellar sources may now be possible.Our CS J = 7 - -> 6 data appear to be tracing gaseous material in the inner circumbin ary core, while the CS J = 5 --> 4 and HCO+ J = 4 --> 3 appear to trac e the outer envelope and static core in addition to the inner circumbi nary core. The mass accretion rate through the infall region appears t o be consistent with an inside-out collapse model for the source. Usin g three-dimensional radiative transfer models based on the rotating, c ollapse solution of Terebey, Shu, & Cassen, we derive the infall param eters of the IRAS 16293-2422 cloud core. Our best-fit model suggests t hat the infall radius of the IRAS 16293 - 2422 cloud core is similar t o 39 '' (0.03 pc).