Complex Organic Molecules tracing shocks along the outflow cavity in the high-mass protostar IRAS 20126+4104
Complex Organic Molecules tracing shocks along the outflow cavity in the high-mass protostar IRAS 20126+4104
复制标题
复杂有机分子追踪高质量原恒星 IRAS 20126 4104 流出腔的激波
DOI：
10.1093/mnras/stx004
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发表时间：
2017
影响因子：
4.8
通讯作者：
Palau A
中科院分区：
文献类型：
--
作者：
Palau A
我们报告亚角秒观测复杂的有机分子（COM）在高质量的原恒星IRAS 20126+4104与高原德布尔干涉仪在其最扩展的配置。除了简单分子SO、HNCO和H213 CO外，我们还检测到CH 3CN、CH 3OH、HCOOH、HCOOCH 3、CH 3 OCH 3、CH 3CH 2CN、CH 3COCH 3、NH 2CN和（CH 2 OH）2的发射。SO和HNCO呈现与追踪流出腔壁一致的X形形态。大多数的COMs在原恒星的假定位置有它们的峰值发射，但也显示出向南（东）的延伸，与来自喷流的H2结在原恒星约800-1000 Au的位置重合。这在H213 CO和CH 3 OCH 3的情况下尤其明显。我们对圆盘和外流的代表性位置的光谱进行了拟合，发现大多数COM的丰度在两个位置都相当，这表明由于外流的通过，COM在冲击中增强。通过耦合一个参数激波模型的一个大的气体颗粒化学网络，包括COM，我们发现，所观察到的COM应该生存在气相中为102000年，相当于从水脉泽在流出位置的冲击寿命估计。总的来说，我们的数据表明，在IRAS 20126+4104中的COM可能不仅来自磁盘，而且还来自与外流相关的密集和炎热的区域。
We report on subarcsecond observations of complex organic molecules (COMs) in the high-mass protostar IRAS 20126+4104 with the Plateau de Bure Interferometer in its most extended configurations. In addition to the simple molecules SO, HNCO and H213CO, we detect emission from CH3CN, CH3OH, HCOOH, HCOOCH3, CH3OCH3, CH3CH2CN, CH3COCH3, NH2CN and (CH2OH)2. SO and HNCO present a X-shaped morphology consistent with tracing the outflow cavity walls. Most of the COMs have their peak emission at the putative position of the protostar, but also show an extension towards the south(east), coinciding with an H2knot from the jet at about 800–1000 au from the protostar. This is especially clear in the case of H213CO and CH3OCH3. We fitted the spectra at representative positions for the disc and the outflow, and found that the abundances of most COMs are comparable at both positions, suggesting that COMs are enhanced in shocks as a result of the passage of the outflow. By coupling a parametric shock model to a large gas–grain chemical network including COMs, we find that the observed COMs should survive in the gas phase for ∼2000 yr, comparable to the shock lifetime estimated from the water masers at the outflow position. Overall, our data indicate that COMs in IRAS 20126+4104 may arise not only from the disc, but also from dense and hot regions associated with the outflow.