UCLCHEM: A Gas-grain Chemical Code for Clouds, Cores, and C-Shocks
UCLCHEM: A Gas-grain Chemical Code for Clouds, Cores, and C-Shocks
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DOI：
10.3847/1538-3881/aa773f
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发表时间：
2017-07-01
影响因子：
5.3
通讯作者：
Priestley, F.
中科院分区：
文献类型：
--
作者：
Holdship, J.;Viti, S.;Priestley, F.
我们提出了一个公开的，开源版本的时间依赖性，气体颗粒化学代码UCLCHEM。UCLCHEM通过在各种物理条件下的化学反应的大型网络传播化学物种的丰度。该模型进行了详细描述，沿着其应用。作为可能用途的一个例子，UCLCHEM用于探索原恒星坍缩对常见分子的影响，并研究C型冲击中分子的行为。我们发现一个简单的Bonnor-Ebert球的坍缩成功地再现了Tafalla等人（2004）观察到的CO，CS和NH3的大部分行为，但不能预测N2 H+的行为。在C-shock的应用中，我们发现分子可以被分类，使它们成为有用的观察示踪剂的冲击和它们的物理性质。虽然许多分子在冲击气体中增强，但我们特别确定了两组分子。当激波传播时，少量的分子被冰的溅射所增强，然后在整个激波过程中保持高丰度。第二个更大的集合也通过溅射得到增强，但随着气体温度的升高而被破坏。通过这些应用，证明了UCLCHEM的普遍适用性。
We present a publicly available, open source version of the time-dependent, gas-grain chemical code UCLCHEM. UCLCHEM propagates the abundances of chemical species through a large network of chemical reactions in a variety of physical conditions. The model is described in detail, along with its applications. As an example of possible uses, UCLCHEM is used to explore the effect of protostellar collapse on commonly observed molecules, and study the behavior of molecules in C-type shocks. We find the collapse of a simple Bonnor-Ebert sphere successfully reproduces most of the behavior of CO, CS, and NH3 from cores observed by Tafalla et al. (2004), but cannot predict the behavior of N2H+. In the C-shock application, we find that molecules can be categorized such that they become useful observational tracers of shocks and their physical properties. Although many molecules are enhanced in shocked gas, we identify two groups of molecules in particular. A small number of molecules are enhanced by the sputtering of the ices as the shock propagates, and then remain high in abundance throughout the shock. A second, larger set is also enhanced by sputtering, but then destroyed as the gas temperature rises. Through these applications, the general applicability of UCLCHEM is demonstrated.