Carbon Chain Chemistry in Hot-core Regions around Three Massive Young Stellar Objects Associated with 6.7 GHz Methanol Masers
Journal article, 2021

We have carried out observations of CCH (N = 1 - 0), CH3CN (J = 5 - 4), and three C-13 isotopologues of HC3N (J = 10 - 9) toward three massive young stellar objects (MYSOs), G12.89+0.49, G16.86-2.16, and G28.28-0.36, with the Nobeyama 45 m radio telescope. Combined with previous results on HC5N, the column density ratios of N(CCH)/N(HC5N), hereafter the CCH/HC5N ratios, in the MYSOs are derived to be similar to 15. This value is lower than that in a low-mass warm carbon chain chemistry (WCCC) source by more than one order of magnitude. We compare the observed CCH/HC5N ratios with hot-core model calculations. The observed ratios in the MYSOs can be best reproduced by models when the gas temperature is similar to 85 K, which is higher than in L1527, a low-mass WCCC source (similar to 35 K). These results suggest that carbon-chain molecules detected around the MYSOs exist at least partially in higher temperature regions than those in low-mass WCCC sources. There is no significant difference in column density among the three C-13 isotopologues of HC3N in G12.89+0.49 and G16.86-2.16, while (HCCCN)-C-13 is more abundant than the others in G28.28-0.36. We discuss carbon-chain chemistry around the three MYSOs based on the CCH/HC5N ratio and the C-13 isotopic fractionation of HC3N.


Massive stars

Interstellar molecules


KotomiFF Taniguchi

Gakushuin University

Eric Herbst

University of Virginia

Liton Majumdar

Homi Bhabha National Institute (HBNI)

Paola Caselli

Max Planck Society

Jonathan Tan

University of Virginia

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Zhi-Yun Li

University of Virginia

Tomomi Shimoikura

Otsuma Women's University

Kazuhito Dobashi

Tokyo Gakugei University

Fumitaka Nakamura

University of Tokyo

National Institutes of Natural Sciences

The Graduate University for Advanced Studies (SOKENDAI)

Masao Saito

National Institutes of Natural Sciences

The Graduate University for Advanced Studies (SOKENDAI)

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 908 1 100

Eld ur is - den massiva stjärnbildningens utvecklingsstadier

Swedish Research Council (VR) (2017-04522), 2018-01-01 -- 2021-12-31.

Subject Categories

Meteorology and Atmospheric Sciences

Astronomy, Astrophysics and Cosmology




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