On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
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DOI：
10.1093/mnras/stx828
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发表时间：
2017-04
影响因子：
4.8
通讯作者：
T. Vidal;J. Loison;A. Jaziri;M. Ruaud;P. Gratier;V. Wakelam
中科院分区：
文献类型：
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作者：
T. Vidal;J. Loison;A. Jaziri;M. Ruaud;P. Gratier;V. Wakelam
含硫物种经常被用来探测星际介质中恒星形成区域的物理结构，但这些区域中硫的化学成分仍然知之甚少。在暗云中，硫应该以一种尚不为人所知的形式被耗尽，尽管已经进行了大量的观测和化学模拟研究。为了改进硫化学模型，我们利用实验和理论文献提出了一种加强硫化学网络的方法。我们使用不同的元素硫丰度测试了更新后的网络对暗云条件下三相气-粒化学模式输出的影响。更具体地说，我们重点研究了主要的硫气藏以及模型预测与在暗云TMC-1(CP)中观测到的丰度之间的一致性。我们的结果表明，根据观测到的云的年龄，硫的储存库可能是气相中的原子硫，也可能是冰粒中的HS和H_2S。我们还报道了第一个能够用硫的宇宙丰度作为元素丰度的化学模型，该模型能够再现TMC-1(CP)中观测到的含S物种的丰度。
Sulphur-bearing species are often used to probe the physical structure of star forming regions of the interstellar medium, but the chemistry of sulphur in these regions is still poorly understood. In dark clouds, sulphur is supposed to be depleted under a form which is still unknown despite numerous observations and chemical modeling studies that have been performed. In order to improve the modeling of sulphur chemistry, we propose an enhancement of the sulphur chemical network using experimental and theoretical literature. We test the effect of the updated network on the outputs of a three phases gas-grain chemical model for dark cloud conditions using different elemental sulphur abundances. More particularly, we focus our study on the main sulphur reservoirs as well as on the agreement between model predictions and the abundances observed in the dark cloud TMC-1 (CP). Our results show that depending on the age of the observed cloud, the reservoir of sulphur could either be atomic sulphur in the gas-phase or HS and H2S in icy grain bulks. We also report the first chemical model able to reproduce the abundances of observed S-bearing species in TMC-1 (CP) using as elemental abundance of sulphur its cosmic value.