CCS OBSERVATIONS OF THE PROTOSTELLAR ENVELOPE OF B335

We present single-dish and interferometric spectral line observations of CCS at 22 GHz toward the core of B335, a classical example of a you ng protostellar region. We combined the VLA and DSN 70 m observations to produce high-resolution (6 '' and 12 '') channel maps at 0.04 km s( -1) velocity intervals. These maps image for the first time the collap sing envelope around the protostar. These show that CCS emission arise s primarily from the outer parts of the collapsing envelope down to ha lf the infall radius and that CCS is clumpy throughout the core. LVG e xcitation analysis indicates that X(CCS) is similar to 3 x 10(-9) in t he outer envelope and less than 5 x 10(-11) in the center of the infal l region. The absence of CCS in the interior could be due to time-depe ndent chemical evolution. The velocity structure supports the evidence for inside-out collapse and the high-velocity features are consistent with accretion onto a rotating central disk. The asymmetric clumpy di stribution of CCS emission implies that the physical conditions are no t spherically symmetric, and that the gas falling onto the circumstell ar disk may be episodic.