Observations of CH3OH and CH3CHO in a Sample of Protostellar Outflow Sources
Observations of CH3OH and CH3CHO in a Sample of Protostellar Outflow Sources
复制标题
原恒星流出源样本中 CH3OH 和 CH3CHO 的观测
DOI：
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发表时间：
2019
影响因子：
4.9
通讯作者：
Sarah Horn
中科院分区：
文献类型：
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作者：
J. Holdship;S. Viti;C. Codella;J. Rawlings;I. Jímenez;Yenabeb Ayalew;J. Curtis;Annur Habib;Jamel E. Lawrence;Sumaya Warsame;Sarah Horn
在96-176 GHz范围内对8个原恒星外流源进行了IRAM 30 m观测。其中7个样品中检测到CH_3OH和CH_3CHO的跃迁。使用RADEX和LTE模型测量和拟合落入所观察到的频率范围内的每个物种的转换的综合发射。列密度和气体性质推断，从这个拟合。CH 3OH的A型和E型异构体的比例表明，在这些流出物中观察到的甲醇是在颗粒表面上形成的。这两个物种表现出减少的终端速度在他们的线配置文件在更快的流出，表明在冲击后的气相破坏。这种破坏，以及CH 3OH和CH 3CHO柱密度的接近恒定的比率，意味着CH 3CHO也很可能在颗粒表面上形成。
IRAM 30 m Observations toward eight protostellar outflow sources were taken in the 96–176 GHz range. Transitions of CH3OH and CH3CHO were detected in seven of them. The integrated emissions of the transitions of each species that fell into the observed frequency range were measured and fit using RADEX and LTE models. Column densities and gas properties inferred from this fitting are presented. The ratio of the A and E-type isomers of CH3OH indicates that the methanol observed in these outflows was formed on the grain surface. Both species demonstrate a reduction of terminal velocity in their line profiles in faster outflows, indicating destruction in the post-shock gas phase. This destruction, and a near constant ratio of the CH3OH and CH3CHO column densities, imply it is most likely that CH3CHO also forms on the grain surface.