标题： Serpens 星形成区的 HCO+、HCN 和 N2H+ 观测研究 显示英文标题

标题： The Serpens Star-Forming Region in HCO+, HCN, and N2H+

摘要： 这份海报展示了对蛇夫座恒星形成区的单碟和孔径合成观测结果，涉及 HCO+、HCN 和 N2H+ 分子的 J=1-0（波长~3 毫米）跃迁。由年轻恒星驱动的喷流会影响其周围云的结构和化学性质，本研究旨在评估这三种分子谱线的发射在多大程度上受这些过程主导。 在蛇夫座中，我发现 N2H+ 1-0 可以追踪总物质的数量，但在两个轻微超前于冲击波的区域除外。相比之下，HCN 和特别是 HCO+ 的发射主要集中在受到外流影响的区域。一个之前未知的强冲击区域位于年轻恒星天体 SMM 4 西北约 0.1 种子距离处。与冲击相关的 HCN 和 N2H+ 发射的峰值之间存在明显的空间偏移。 我构建了一个简单的定性化学模型，在该模型中，N2H+ 的发射在 C 型冲击的磁前驱物中增加，而在冲击深处随着中性粒子加热，像 HCN 和水等物种从冰冻的尘埃颗粒表面释放出来时，N2H+ 被破坏。 我得出结论，N2H+ 是云物质的一个可靠示踪剂，并且未解析的 HCO+ 和 HCN 观测结果将主要受外流影响的物质所主导。 显示英文摘要

摘要： This poster presents single-dish and aperture-synthesis observations of the J=1-0 (lambda~3 mm) transitions of HCO+, HCN, and N2H+ towards the Serpens star-forming region. Jets driven by young stars affect the structure and the chemistry of their surrounding cloud, and this work aims to assess the extent to which the emission of these three molecular lines is dominated by such processes. In Serpens I find that N2H+ 1-0 traces the total amount of material, except in two regions slightly ahead of shocks. In contrast, the HCO+ and, especially, HCN emission is dominated by regions impacted by outflows. One previously unknown, strongly shocked region is located ~0.1 pc northwest of the young stellar object SMM 4. There is a marked spatial offset between the peaks in the HCN and the N2H+ emission associated with shocked regions. I construct a simple, qualitative chemical model where the N2H+ emission increases in the magnetic precursor of a C-type shock, while N2H+ is destroyed deeper in the shock as the neutrals heat up and species like HCN and water are released from icy grain mantles. I conclude that N2H+ is a reliable tracer of cloud material, and that unresolved observations of HCO+ and HCN will be dominated by material impacted by outflows.