Oxygen fractionation in dense molecular clouds.
Oxygen fractionation in dense molecular clouds.
复制标题
密集分子云中的氧分馏。
DOI：
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发表时间：
2019
影响因子：
4.8
通讯作者：
P. Riviere
中科院分区：
文献类型：
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作者：
J. Loison;V. Wakelam;P. Gratier;K. Hickson;A. Bacmann;M. Agúndez;N. Marcelino;J. Cernicharo;V. Guzmán;M. Gerin;J. Goicoechea;È. Roueff;F. Petit;J. Pety;A. Fuente;P. Riviere
我们已经开发了致密分子云中氧分馏（也包括硫分馏）的第一个气相颗粒化学模型，证明气相化学产生可变的氧分馏水平，对NO， SO， O2和SO2的影响特别强。这种巨大的影响是由于中性的18O + NO， 18O + SO和18O + O2交换反应的效率。将模拟结果与在选定的冷岩心中新的和现有的观测到的同位素比率进行了比较。模型与观测值之间的良好一致性要求观测区域中中性氧原子的气相丰度较大。预计S16O/S18O比值随时间变化很大，表明它可以作为致密分子云中物质演化的敏感化学指标。
We have developed the first gas-grain chemical model for oxygen fractionation (also including sulphur fractionation) in dense molecular clouds, demonstrating that gas-phase chemistry generates variable oxygen fractionation levels, with a particularly strong effect for NO, SO, O2, and SO2. This large effect is due to the efficiency of the neutral 18O + NO, 18O + SO, and 18O + O2 exchange reactions. The modeling results were compared to new and existing observed isotopic ratios in a selection of cold cores. The good agreement between model and observations requires that the gas-phase abundance of neutral oxygen atoms is large in the observed regions. The S16O/S18O ratio is predicted to vary substantially over time showing that it can be used as a sensitive chemical proxy for matter evolution in dense molecular clouds.