Chemical modelling of glycolaldehyde and ethylene glycol in star-forming regions
Chemical modelling of glycolaldehyde and ethylene glycol in star-forming regions
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DOI：
10.1093/mnras/stx3335
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发表时间：
2017-12
影响因子：
4.8
通讯作者：
A. Coutens;S. Viti;J. Rawlings;M. Beltr'an;J. Holdship;I. Jim'enez-Serra;D. Qu'enard;V. Rivilla
中科院分区：
文献类型：
--
作者：
A. Coutens;S. Viti;J. Rawlings;M. Beltr'an;J. Holdship;I. Jim'enez-Serra;D. Qu'enard;V. Rivilla
乙醇醛（HOCH $_2 $CHO）和乙二醇（（CH $_2 $OH）$_2 $）是在几个恒星形成区的热核和热科里醇中检测到的两种复杂的有机分子。乙二醇/乙醇醛的丰度比似乎显示出与源光度的增加。在文献中，已经提出了这两个物种的几种表面化学形成机制。使用UCLCHEM化学代码，我们探索了不同的场景，并将一系列不同光度的来源的预测与观测结果进行了比较。没有一种情况能完美地再现这一趋势。一个更好的协议，但是，发现通过重组的两个HCO自由基，然后连续氢化的形成。除了加氢途径之外，HCO与CH $_2 $OH之间的反应也可能有助于乙醇醛的形成。当在核心区域内的H$_2 $密度随着T $\geq $100 K作为光度的函数而降低的趋势被包括在模型中时，预测得到改善。还需要研究复杂有机分子在气相中的破坏反应，因为一旦物种在恒星形成区域的温暖内部区域解吸，它们就会影响丰度比。
Glycolaldehyde (HOCH$_2$CHO) and ethylene glycol ((CH$_2$OH)$_2$) are two complex organic molecules detected in the hot cores and hot corinos of several star-forming regions. The ethylene glycol/glycolaldehyde abundance ratio seems to show an increase with the source luminosity. In the literature, several surface-chemistry formation mechanisms have been proposed for these two species. With the UCLCHEM chemical code, we explored the different scenarios and compared the predictions for a range of sources of different luminosities with the observations. None of the scenarios reproduce perfectly the trend. A better agreement is, however, found for a formation through recombination of two HCO radicals followed by successive hydrogenations. The reaction between HCO and CH$_2$OH could also contribute to the formation of glycolaldehyde in addition to the hydrogenation pathway. The predictions are improved when a trend of decreasing H$_2$ density within the core region with T $\geq$ 100 K as a function of luminosity, is included in the model. Destruction reactions of complex organic molecules in the gas phase would also need to be investigated, since they can affect the abundance ratios once the species have desorbed in the warm inner regions of the star-forming regions.