Physical and Chemical Diversity of Star-Forming Regions and Its Propagation to Protoplanetary Disks

最近，人们认识到，低质量的0类源显示出显着的化学多样性。在这项研究中，我们集中在一个极端的情况下，显示异常丰富的碳链分子在一个不冷不热的区域附近的原恒星（温暖的碳链化学; WCCC），并观察研究其起源和它的演变向I类阶段。以下是主要成果。首先，我们在WCCC源IRAS 15398 -3359附近新发现了一个年轻的无星核心，具有丰富的碳链分子，Lupus-1A。另一个WCCC源L1527也位于类似的年轻无星核心TMC-1附近。这一结果进一步支持了WCCC起源于母核快速收缩的假设。其次，我们用PdBI研究了L1527中碳链分子的高分辨分布。碳链分子的致密分布支持了原恒星附近CH_4蒸发触发的WCCC机制。更重要的是，碳链分子甚至被发现存在于落入原恒星的气体中，这表明碳链分子将被带入原行星盘。我们已经搜索了WCCC活动的1类源，并确实在L1527附近找到了这样一个例子。在这项研究中，我们获得了新的信息，WCCC源将如何演变为原行星盘。

Recently, it is recognized that the low-mass Class 0 sources shows significant chemical diversity. In this study, we have focused on one extreme case showing extraordinary richness of carbon-chain molecules in a lukewarm region near the protostar (Warm Carbon-Chain Chemistry ; WCCC), and have observationally studied its origin and its evolution toward the Class I stage. The followings are major outcomes. First, we have newly found a young starless core with rich carbon-chain molecules, Lupus-1A, near the WCCC source IRAS15398-3359. The other WCCC source, L1527, is also located near the similar young starless core TMC-1. This result further supports our scenario that the WCCC originates from fast contraction of the parent core. Second, we have studied high-resolution distributions of carbon-chain molecules in L1527 with PdBI. Compact distributions of carbon-chain molecules support the WCCC mechanism triggered by the evaporation of CH_4 near the protostar. More importantly, carbon-chain molecules are found to reside even in the gas infalling to the protostar, suggesting that carbon-chain molecules will be brought into protoplanetary disks. We have searched for the Class 1 sources with the WCCC activities, and have indeed found such an example near L1527. In this study, we have obtained novel information on how the WCCC sources will be evolved toward protoplanetary disks.