On modelling cosmic ray sputtering of interstellar grain ices
On modelling cosmic ray sputtering of interstellar grain ices
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星际颗粒冰的宇宙射线溅射建模
DOI：
10.1093/mnras/stac2507
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发表时间：
2022
影响因子：
4.8
通讯作者：
Herbst, Eric
中科院分区：
文献类型：
--
作者：
Paulive, Alec;Carder, Joshua T.;Herbst, Eric
在星际介质（ISM）中，复杂有机分子（COMs）的形成在很大程度上由表面反应促进。然而，在寒冷的乌云，COMs的热解吸是低效的，因为缺乏热能来克服结合能的粮食表面。因此，非热解吸方法是重要的解释气相检测的许多COM主要是在晶粒上形成。在这里，我们提出了一个新的非热解吸过程：宇宙射线溅射的颗粒冰表面的水，二氧化碳，和一个简单的混合冰。我们的模型适用于估计的溅射率的三相速率方程modelnautilus-1.1，其中这种夹杂物的结果在增强气相丰度的颗粒反应，如甲醇（CH 3OH）和甲酸甲酯（HCOOCH 3）产生的分子。值得注意的是，与其他分子相比，具有有效气相破坏途径的物种在具有溅射的模型中表现出较少的增加。这些模型的结果表明，溅射是一种有效的，非特异性的非热解吸方法，应被视为在未来的化学模型的一个重要因素。
In the interstellar medium (ISM), the formation of complex organic molecules (COMs) is largely facilitated by surface reactions. However, in cold dark clouds, thermal desorption of COMs is inefficient because of the lack of thermal energy to overcome binding energies to the grain surface. Non-thermal desorption methods are therefore important explanations for the gas-phase detection of many COMs that are primarily formed on grains. Here, we present a new non-thermal desorption process: cosmic ray sputtering of grain ice surfaces based on water, carbon dioxide, and a simple mixed ice. Our model applies estimated rates of sputtering to the three-phase rate equation modelnautilus-1.1, where this inclusion results in enhanced gas-phase abundances for molecules produced by grain reactions such as methanol (CH3OH) and methyl formate (HCOOCH3). Notably, species with efficient gas-phase destruction pathways exhibit less of an increase in models with sputtering compared to other molecules. These model results suggest that sputtering is an efficient, non-specific method of non-thermal desorption that should be considered as an important factor in future chemical models.