Physical and Chemical Properties of Massive Clumps in the AFGL 333 Cloud
Physical and Chemical Properties of Massive Clumps in the AFGL 333 Cloud
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DOI：
10.1086/518402
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发表时间：
2007-06
期刊：
影响因子：
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通讯作者：
T. Sakai;T. Oka;S. Yamamoto
中科院分区：
文献类型：
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作者：
T. Sakai;T. Oka;S. Yamamoto
我们利用野山射电天文台45米望远镜绘制了AFGL 333星云在N2H+ J = 1-0、CCS JN = 43-32、HC3N J = 5-4和NH3 (J，K) =(1,1)和（2,2）线上的两个大团A和团B。两团块均有较强的N2H+发射，其总体分布与C18O J = 1-0相似。另一方面，CCS和HC3N对团B的发射强度大于对团A的发射强度。因此，[CCS]/[N2 H+]和[HC3N]/[N2H+]的柱密度比对团B的密度比对团A的密度大，表明团B比团A年轻，这一事实也支持了含H - K bbb2的2MASS源和Spitzer 24 μm源主要与团A相关的事实。而在星系团B中只有少数这样的源存在。星系团B包含一些致密的核，在中红外图中是暗的。这样的核心被认为是高质量或中等质量恒星的无恒星核心的良好候选者。
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.