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

2023/07/25 by Yanan Feng, Feng, Yanan, Xiaohu Li +34 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies

paper · pdf · doi:10.48550/arxiv.2307.13216

openalex publication_date 2023/07/25 · openalex created_date 2023/07/27 · openalex updated_date 2026/07/28

Abstract

Whether SiC₂ is a parent species, that is formed in the photosphere or as a by-product of high-temperature dust formation, or a daughter species, formed in a chemistry driven by the photodestruction of parent species in the outer envelope, has been debated for a long time. Here, we analyze the ALMA observations of four SiC₂ transitions in the CSEs of three C-rich AGB stars (AI Vol, II Lup, and RAFGL 4211), and found that SiC₂ exhibits an annular, shell-like distribution in these targets, suggesting that SiC₂ can be a daughter species in the CSEs of carbon-rich AGB stars. The results can provide important references for future chemical models.

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