ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XXI. A Large-sample Observational Study of Ethanol and Dimethyl Ether in Hot Cores

Zhiping Kou; Xiaohu Li; Sheng-Li Qin; Tie Liu; E. Mannfors; Xindi Tang; Prasanta Gorai; Guido Garay; Swagat R. Das; Pablo García; Leonardo Bronfman; M. Juvela; Li Chen; Xunchuan Liu; Patricio Sanhueza; Yaping Peng; Long-Fei Chen; Jiahang Zou; Dongting Yang; L. Viktor Tóth; Lokesh Dewangan; Hong-Li Liu; James O. Chibueze; Ziyang Li

arXiv · 2503.07126

ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XXI. A Large-sample Observational Study of Ethanol and Dimethyl Ether in Hot Cores

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Abstract

Hot cores, as a stage of massive star formation, exhibit abundant line emissions of COMs. We present a deep line survey of two isomers of C$_2$H$_6$O: ethanol (C$_2$H$_5$OH; EA), and dimethyl ether (CH$_3$OCH$_3$; DE) as well as their possible precursor CH$_3$OH towards 60 hot cores by using the ALMA 3 mm line observations. EA is detected in 40 hot cores and DE is detected in 59 hot cores. Of these, EA and DE are simultaneously detected in 39 hot cores. We calculate rotation temperatures and column densities of EA and DE by using the XCLASS software. The average rotation temperature of EA is higher than that of DE, whereas the average column density of EA is lower than that of DE. Combined with previous studies of hot cores and hot corinos, we find strong column density correlations among EA and DE ($\rho$ = 0.92), EA and CH$_3$OH ($\rho$ = 0.82), as well as DE and CH$_3$OH ($\rho$ = 0.80). The column density ratios of EA/DE versus the column densities of CH$_3$OH remain nearly constant with values within ~ 1 order of magnitude. These strong correlations and the stable ratios, suggest that EA, DE, and CH$_3$OH could be chemically linked, with CH$_3$OH potentially serving as a precursor for EA and DE. Compared with chemical models, the three different warm-up timescale models result in the systematic overproduction of EA and the systematic underproduction of DE. Therefore, our large sample observations can provide crucial constraints on chemical models.

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Zhiping Kou, Xiaohu Li, Sheng-Li Qin, Tie Liu, E. Mannfors, Xindi Tang, Prasanta Gorai, Guido Garay, Swagat R. Das, Pablo García, Leonardo Bronfman, M. Juvela, Li Chen, Xunchuan Liu, Patricio Sanhueza, Yaping Peng, Long-Fei Chen, Jiahang Zou, Dongting Yang, L. Viktor Tóth, Lokesh Dewangan, Hong-Li Liu, James O. Chibueze, Ziyang Li. 2025-03-10. ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XXI. A Large-sample Observational Study of Ethanol and Dimethyl Ether in Hot Cores. https://arxiv.org/abs/2503.07126

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