The Abundance of SiC${}_2$ in Carbon Star Envelopes

Abstract

Silicon carbide dust grains are ubiquitous in circumstellar envelopes around C-rich AGB stars. However, the main gas-phase precursors leading to the formation of SiC dust have not yet been identified. To date, only three molecules containing an Si--C bond have been identified to have significant abundances in C-rich AGB stars: SiC${}_2$, SiC, and Si${}_2$C. The ring molecule SiC${}_2$ has been observed in a handful of evolved stars, while SiC and Si${}_2$C have only been detected in the C-star envelope IRC +10216. We aim to study how widespread and abundant SiC${}_2$, SiC, and Si${}_2$C are in envelopes around C-rich AGB stars and whether or not these species play an active role as gas-phase precursors of silicon carbide dust in the ejecta of carbon stars.

Poster presentation to be published in: Proceedings of the IAU Symposium No. 332, 2017, Puerto Varas, Chile. M. Cunningham, T. Millar and Y. Aikawa, eds., (10 pages, 5 figures, 2 tables)

References in corpus (7)

• A Detailed Analysis of the Dust Formation Zone of IRC+10216 Derived from Mid-IR Bands of C2H2 and HCN
• Discovery of SiCSi in IRC+10216: A missing link between gas and dust carriers of SiC bonds
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• A molecular line survey of the extreme carbon star CRL 3068 at millimeter wavelengths
• Spectroscopic parameters for silacyclopropynylidene, SiC${}_2$, from extensive astronomical observations toward CW Leo (IRC +10216) with the Herschel satellite