论文标题
银河系尺度动力学对冷和密集ISM III分子组成的影响。当前物理化学模型的元素耗竭和缺点
Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM III. Elemental depletion and shortcomings of the current physico-chemical models
论文作者
论文摘要
我们介绍了星际培养基中元素耗竭的研究。我们结合了一个元模型的结果，该模型描述了使用全加气体化学模型形成密集芯过程中气体物理条件的结果。在扩散培养基和致密培养基之间的过渡过程中，元素的储层（最初是气体中的原子质）逐渐消耗在灰尘晶粒上（对于离子的那些阶段的中和阶段）。当密度大于100〜cm $^{ - 3} $时，此过程变得有效。如果密集的材料回到弥漫条件中，则由于分子在冰上的照片分解，然后将这些元素带回气相中，然后从晶粒中进行热解动。低于10〜cm $^{ - 3} $的密度或以分子形式的气相中的密度没有任何内容。氯是一个例外，该氯在低密度下有效地转化。我们当前的气体晶粒化学模型无法再现在弥漫培养基中观察到的原子的耗竭，除了cl的气体丰度遵循观察到的一个在密度小于10〜cm $ $^{ - 3} $的培养基中。这表明至关重要的过程（可能涉及化学吸附和/或冰辐射深刻地改变了冰的性质）。
We present a study of the elemental depletion in the interstellar medium. We combined the results of a Galatic model describing the gas physical conditions during the formation of dense cores with a full-gas-grain chemical model. During the transition between diffuse and dense medium, the reservoirs of elements, initially atomic in the gas, are gradually depleted on dust grains (with a phase of neutralisation for those which are ions). This process becomes efficient when the density is larger than 100~cm$^{-3}$. If the dense material goes back into diffuse conditions, these elements are brought back in the gas-phase because of photo-dissociations of the molecules on the ices followed by thermal desorption from the grains. Nothing remains on the grains for densities below 10~cm$^{-3}$ or in the gas-phase in a molecular form. One exception is chlorine, which is efficiently converted at low density. Our current gas-grain chemical model is not able to reproduce the depletion of atoms observed in the diffuse medium except for Cl which gas abundance follows the observed one in medium with densities smaller than 10~cm$^{-3}$. This is an indication that crucial processes (involving maybe chemisorption and/or ice irradiation profoundly modifying the nature of the ices) are missing.
