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Clues to NaCN formation?

机译：形成NaCN的线索？

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Context. ALMA is providing us essential information on where certain molecules form. Observing where these molecules emission arises from, the physical conditions of the gas, and how this relates with the presence of other species allows us to understand the formation of many species, and to significantly improve our knowledge of the chemistry that occurs in the space. Aims. We studied the molecular distribution of NaCN around IRC?+10216, a molecule detected previously, but whose origin is not clear. High angular resolution maps allow us to model the abundance distribution of this molecule and check suggested formation paths. Methods. We modeled the emission of NaCN assuming local thermal equilibrium (LTE) conditions. These profiles were fitted to azimuthal averaged intensity profiles to obtain an abundance distribution of NaCN. Results. We found that the presence of NaCN seems compatible with the presence of CN, probably as a result of the photodissociation of HCN, in the inner layers of the ejecta of IRC?+10216. However, similar as for CH3CN, current photochemical models fail to reproduce this CN reservoir. We also found that the abundance peak of NaCN appears at a radius of 3 × 1015 cm, approximately where the abundance of NaCl, suggested to be the parent species, starts to decay. However, the abundance ratio shows that the NaCl abundance is lower than that obtained for NaCN. We expect that the LTE assumption might result in NaCN abundances higher than the real ones. Updated photochemical models, collisional rates, and reaction rates are essential to determine the possible paths of the NaCN formation.
机译：上下文。 ALMA正在向我们提供有关某些分子形成位置的基本信息。观察这些分子的发射源于何处，气体的物理条件以及这与其他物种的存在之间的关系，可以使我们了解许多物种的形成，并极大地提高我们对空间化学的认识。目的我们研究了IRC？+10216附近NaCN的分子分布，IRC？+10216是先前检测到的分子，但其起源尚不清楚。高角度分辨率图使我们能够为该分子的丰度分布建模并检查建议的形成路径。方法。我们在假设局部热平衡（LTE）条件下对NaCN的排放进行建模。将这些轮廓拟合到方位角平均强度轮廓，以获得NaCN的丰度分布。结果。我们发现NaCN的存在似乎与CN的存在相容，可能是由于HCN的光解离作用在IRCα+ 10216的喷出层的内层。但是，与CH3CN相似，当前的光化学模型无法复制此CN储层。我们还发现，NaCN的丰度峰出现在半径3×1015 cm处，大约是建议作为母体的NaCl的丰度开始衰减的位置。但是，丰度比表明NaCl的丰度低于NaCN的丰度。我们预计LTE假设可能会导致NaCN的丰度高于真实的丰度。更新的光化学模型，碰撞速率和反应速率对于确定NaCN形成的可能途径至关重要。

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