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 J_N = 4₃-3 ₂, HC₃N J = 5-4, and NH₃ (J, K) = (1,1) and (2,2) lines with the Nobeyama Radio Observatory 45 m telescope. Intense N ₂H⁺ 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.