论文标题
在热的corinos中的甲基氨基甲酸酯(甘氨酸异构体)的形成和丰度的约束
Constraints of the formation and abundances of methyl carbamate, a glycine isomer, in hot corinos
论文作者
论文摘要
甲基氨基甲酸酯ch $ _3 $ oc(o)NH $ _2 $是甘氨酸的异构体。量子化学分析表明,甲基氨基甲酸酯比甘氨酸更稳定。因此,与甘氨酸相比,在星际培养基中存在甲基碳水化合物的可能性更高。尽管进行了巨大的搜索,但直到现在尚未在ISM中检测到甘氨酸,因此值得搜索其异构体甲基氨基甲酸酯。在本文中,我们介绍了星际条件下甲基氨基甲酸酯形成的约束。大型有机分子在低质量质体的热孔环境中产生有利。我们首次进行了大量的天体化学建模,重点是在类似于热 - 咖喱物体的物理条件下形成甲基氨基甲酸酯。因此,我们检查了ALMA档案数据的现有光谱线观测值,该观测值对Hot Corinos NGC1333 IRAS 4A2和IRAS 16293B。在朝向这些源的公共光谱范围内,我们发现三个特征可能与甲基氨基甲酸酯的光谱过渡有关,因此估计了色谱柱密度的上限。化学建模的结果与估计的色谱柱密度/丰度对源的观察上限一致。这可能会暗示拟议的形成机制的验证。使用NGVLA等望远镜的未来观察可能会证实MC朝向热的Corinos。
Methyl carbamate CH$_3$OC(O)NH$_2$ is an isomer of glycine. Quantum chemical analyses show that methyl carbamate is more stable isomer than glycine. Because of this, there could be a higher chance for methyl carbamte to exist in the interstellar medium as compared to glycine. Despite immense searches, till now glycine has not been detected in the ISM, therefore it is worthwhile to search its isomer methyl carbamate. In this paper, we present the constraints of methyl carbamate formation under the interstellar conditions. Large complex organic molecules are favorably produced in hot-corino environments of low mass protostars. We for the first time carried out astrochemical modeling focusing on the formation of methyl carbamate in physical conditions similar to hot-corino objects. Consequently, we examined ALMA archival data for existing spectral line observations toward hot corinos NGC1333 IRAS 4A2 and IRAS 16293B. Within the common spectral range towards these sources, we found three features are possibly related to the spectral transitions of methyl carbamate and consequently estimate the upper limit of column densities. Results of chemical modeling are consistent with the observational upper limit of estimated column density/abundance toward the sources. This may hint the validation of the proposed formation mechanism. Future observations using telescope like ngVLA may confirm the presence of MC toward the hot corinos.