Photochemical origin of SiC2 in the circumstellar envelope of carbon-rich AGB stars revealed by ALMA

The fact that whether SiC 2 is a parent species, formed in the photosphere or as a by-product of high-temperature dust formation, or a daughter species, formed in chemistry driven by the photodestruction of the parent species in the outer envelope, has been debated for a long time. In this study, we...

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Bibliographic Details
Published in:Frontiers in astronomy and space sciences 2023-08, Vol.10
Main Authors: Feng, Yanan, Li, Xiaohu, Millar, Tom J., Szczerba, Ryszard, Wang, Ke, Quan, Donghui, Qin, Shengli, Fang, Xuan, Tuo, Juan, Miao, Zhenzhen, Ma, Rong, Xu, Fengwei, Sun, Jingfei, Jiang, Biwei, Chang, Qiang, Yang, Jianchao, Hou, Gao-Lei, Li, Fangfang, Zhang, Yong
Format: Article
Language:English
Subjects:
AI Vol
asymptotic giant branch stars
C-rich
circumstellar envelope
mass loss
SiC2
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Summary:The fact that whether SiC 2 is a parent species, formed in the photosphere or as a by-product of high-temperature dust formation, or a daughter species, formed in chemistry driven by the photodestruction of the parent species in the outer envelope, has been debated for a long time. In this study, we analyze the Atacama Large Millimeter Array (ALMA) observations of four SiC 2 transitions in the circumstellar envelopes (CSEs) of three C-rich asymptotic giant branch (AGB) stars (AI Vol, II Lup, and RAFGL 4211) and find that SiC 2 exhibits an annular, shell-like distribution in these targets, suggesting that SiC 2 can be a daughter species in the CSEs of carbon-rich AGB stars. The results may provide important references for future chemical models.
ISSN:2296-987X
2296-987X
DOI:10.3389/fspas.2023.1215642