Physical and Chemical Properties of Massive Clumps in the AFGL 333 Cloud

We have mapped two massive clumps, clump A and B, of the AFGL 333 cloud in the N2H+ J = 1-0, CCS JN = 43-32, HC3N J = 5-4, and NH3 (J,K) = (1,1) and (2,2) lines with the Nobeyama Radio Observatory 45 m telescope. Intense N2H+ emission comes from the two clumps, and its overall distribution is similar to that of C18O J = 1-0. On the other hand, the CCS and HC3N emissions are more intense toward clump B than toward clump A. Thus, the column density ratios of [CCS]/[N2 H+] and [HC3N]/[N2H+] tend to be higher toward clump B than toward clump A, indicating that clump B is younger than clump A. This is supported by a fact that the 2MASS sources with H - K > 2 and the Spitzer 24 μm sources are mostly associated with clump A, whereas only a few such sources exist in clump B. Clump B involves a few dense cores that are dark in the mid-infrared maps. Such cores are thought to be good candidates of starless cores for high- or intermediate-mass stars.