Understanding the chemical complexity in Circumstellar Envelopes of C-Rich AGB stars: the case of IRC +10216
Understanding the chemical complexity in Circumstellar Envelopes of C-Rich AGB stars: the case of IRC +10216
复制标题
了解富含 C AGB 恒星的星周包络中的化学复杂性：以 IRC 10216 为例
DOI：
10.1007/s10509-007-9495-7
复制
发表时间：
2007
影响因子：
1.9
通讯作者：
A. Apponi
中科院分区：
文献类型：
--
作者：
M. Agúndez;J. Cernicharo;J. Pardo;J. P. Fonfría Expósito;M. Guélin;E. Tenenbaum;L. Ziurys;A. Apponi
摘要
富含碳的AGB星的星周包层显示出化学的复杂性，典型的天体irc+10216就是一个例证，到目前为止，已经探测到大约60个不同的分子。这些物种中的大多数是CNH、CnH2、CNN、HCnN类型的碳链。我们用IRAM 30米望远镜和一些ARO 12米观测，对新物种(CH_2CHCN、CH_2CN、H_2CS、CH_3CCH和C_3O)进行了探测。所有这些已知存在于星际介质中的物种，都是第一次在AGB恒星周围的星际包层中被探测到的。这五个分子很可能是在外部膨胀的包层中形成的，而不是在恒星光球层中形成的。星周包层的纯气相化学模型在解释导出的丰度方面相当成功，此外还允许阐明化学形成路线并预测所检测到的物种的空间分布。
Abstract
The circumstellar envelopes of carbon-rich AGB stars show a chemical complexity that is exemplified by the prototypical object IRC +10216, in which about 60 different molecules have been detected to date. Most of these species are carbon chains of the type CnH, CnH2, CnN, HCnN. We present the detection of new species (CH2CHCN, CH2CN, H2CS, CH3CCH and C3O) achieved thanks to the systematic observation of the full 3 mm window with the IRAM 30m telescope plus some ARO 12m observations. All these species, known to exist in the interstellar medium, are detected for the first time in a circumstellar envelope around an AGB star. These five molecules are most likely formed in the outer expanding envelope rather than in the stellar photosphere. A pure gas phase chemical model of the circumstellar envelope is reasonably successful in explaining the derived abundances, and additionally allows to elucidate the chemical formation routes and to predict the spatial distribution of the detected species.