CM WAVELENGTH SPECTRAL-LINE MAPPING OF PROTOSTELLAR CORES

We study the structure and chemistry of the protostellar core B335 usi ng high resolution spectral line observations of CCS with both single dish antennas and interferometers at cm wavelengths. B335 is a classic al example of a young protostellar region containing both outflow and infall and is an ideal testbed for theoretical models of the collapse phase of protostar formation. We use combined VLA and single dish data to image the core around the protostar in B335. We find that CCS trac es the outer parts of a collapsing envelope with a velocity and spatia l structure consistent with dynamical models. However, CCS is absent i n the interior of the infalling envelope which can only be explained w ith time dependent models of the protostar chemistry. Our work demonst rates the importance of spectral line mapping at cm wavelengths for un derstanding protostar evolution.