论文标题
连接蛇质恒星形成区域中的冰和气
Linking ice and gas in the Serpens low-mass star-forming region
论文作者
论文摘要
恒星形成过程中灰尘,冰和气体之间的相互作用会产生复杂的有机分子。虽然观察结果表明在冰覆盖的灰尘颗粒上形成了几种物种并被释放到气相中,但固体和气相之间的确切化学相互作用及其相对重要性尚不清楚。我们的目标是通过冰和气体映射研究低质量恒星形成区域的相互作用,并直接测量气体与冰比。这提供了导致在两个阶段观察到的化学复杂性的途径的约束。我们对气相甲醇(Ch $ _3 $ OH)和一氧化碳的观察结果为1.3毫米,朝着亚毫米阵列和Atacama Pathfinder tereascope中的Serpens SVS4簇中的十个低质量的年轻原恒星。我们使用了来自非常大型望远镜的档案数据来推导大量的冰h $ _2 $ o,co和ch $ _3 $ oh oh to同一地区。最后,我们构建了SVS4的气冰图,并直接测量了CO和CH $ _3 $ OH气体与冰的比率。 CH $ _3 $ OH气体比率与以前报道的嵌入式0/I低质量质恒定的值一致。 CO气体映射跟踪不敏感的冻结效果的扩展气体组件。我们发现,CO和CH $ _3 $ OH GES与冰层中的冰上的气体之间没有直接的相关性。这可能与SVS4的复杂形态有关:0类Protostar SMM4及其包膜位于附近,与SMM4相关的流出与群集相交。这项研究是与Alma和James Webb太空望远镜进行未来观察的探路者,该望远镜将提供比甲醇更复杂的分子的高敏感性气冰图。这种比较图对于限制调节星形区域化学复杂性的化学途径至关重要。
The interaction between dust, ice, and gas during the formation of stars produces complex organic molecules. While observations indicate that several species are formed on ice-covered dust grains and are released into the gas phase, the exact chemical interplay between solid and gas phases and their relative importance remain unclear. Our goal is to study the interplay in regions of low-mass star formation through ice- and gas-mapping and by directly measuring gas-to-ice ratios. This provides constraints on the routes that lead to the chemical complexity that is observed in both phases. We present observations of gas-phase methanol (CH$_3$OH) and carbon monoxide at 1.3 mm towards ten low-mass young protostars in the Serpens SVS4 cluster from the SubMillimeter Array and the Atacama Pathfinder EXperiment telescope. We used archival data from the Very Large Telescope to derive abundances of ice H$_2$O, CO, and CH$_3$OH towards the same region. Finally, we constructed gas-ice maps of SVS4 and directly measured CO and CH$_3$OH gas-to-ice ratios. The CH$_3$OH gas-to-ice ratio agrees with values that were previously reported for embedded Class 0/I low-mass protostars. The CO gas-maps trace an extended gaseous component that is not sensitive to the effect of freeze-out. We find that there is no straightforward correlation between CO and CH$_3$OH gas with their ice counterparts in the cluster. This is likely related to the complex morphology of SVS4: the Class 0 protostar SMM4 and its envelope lie in the vicinity, and the outflow associated with SMM4 intersects the cluster. This study serves as a pathfinder for future observations with ALMA and the James Webb Space Telescope that will provide high-sensitivity gas-ice maps of molecules more complex than methanol. Such comparative maps will be essential to constrain the chemical routes that regulate the chemical complexity in star-forming regions.