论文标题
在热分子芯中鉴定异氰酸甲酯和其他复合有机分子G31.41+0.31
Identification of Methyl Isocyanate and Other Complex Organic Molecules in a Hot Molecular Core, G31.41+0.31
论文作者
论文摘要
G31.41+0.31是一种众所周知的化学热分子核（HMC）。使用ATACAMA大毫米阵列（ALMA）的Band 3观测值，我们分析了来源的化学和物理性质。我们已经确定了异氰酸甲酯（CH3NCO），这是益生元分子的前体，朝向来源。除此之外，我们还报道了复杂的有机分子（COM），例如甲醇（CH3OH），甲烷硫醇（CH3SH）和甲基甲酸甲酯（CH3OCHO）。此外，我们使用了来自HCN，HCO+，SIO等分子的过渡来追踪恒星形成区域周围的插入和流出特征的存在。对于COM，假设在局部热力学平衡（LTE）条件下分子激发，我们估计了柱密度和动力学温度。根据某些COM的估计动力学温度，我们发现HMC环境中可能存在多个温度成分。将现有观测结果与其他HMC之间获得的分子柱密度进行比较，似乎COM在热核环境中产生了有利的（$ \ sim 100 $ K或更高）。尽管对G31.41+0.31的光谱排放尚未完全解决，但我们发现CH $ _3 $ NCO和其他COM可能在谷物/冰期上形成，并填充类似于SGR B2，Orion KL和G10.47+0.03等其他热核的气体环境。
G31.41+0.31 is a well known chemically rich hot molecular core (HMC). Using Band 3 observations of Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, towards the source. In addition to this, we have reported complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, HCO+, SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming molecular excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained molecular column densities between the existing observational results toward other HMCs, it seems that the COMs are favourably produced in the hot-core environment ($\sim 100$ K or higher). Though the spectral emissions towards G31.41+0.31 are not fully resolved, we find that CH$_3$NCO and other COMs are possibly formed on the grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03, etc.
