Chemical Differentiation around Five Massive Protostars Revealed by ALMA: Carbon-chain Species and Oxygen/Nitrogen-bearing Complex Organic Molecules
Journal article, 2023
We present Atacama Large Millimeter/submillimeter Array Band 3 data toward five massive young stellar objects (MYSOs), and investigate relationships between unsaturated carbon-chain species and saturated complex organic molecules (COMs). An HC5N (J = 35-34) line has been detected from three MYSOs, where nitrogen (N)-bearing COMs (CH2CHCN and CH3CH2CN) have been detected. The HC5N spatial distributions show compact features and match with a methanol (CH3OH) line with an upper-state energy around 300 K, which should trace hot cores. The hot regions are more extended around the MYSOs where N-bearing COMs and HC5N have been detected compared to two MYSOs without these molecular lines, while there are no clear differences in the bolometric luminosity and temperature. We run chemical simulations of hot-core models with a warm-up stage, and compare with the observational results. The observed abundances of HC5N and COMs show good agreements with the model at the hot-core stage with temperatures above 160 K. These results indicate that carbon-chain chemistry around the MYSOs cannot be reproduced by warm carbon-chain chemistry, and a new type of carbon-chain chemistry occurs in hot regions around MYSOs.
Author
Kotomi Taniguchi
National Institutes of Natural Sciences
Liton Majumdar
National Institute of Science Education and Research
Homi Bhabha National Institute (HBNI)
Paola Caselli
Max Planck Institute for Extraterrestrial Physics
Shigehisa Takakuwa
Kagoshima University
Academia Sinica
Tien-Hao Hsieh
Max Planck Institute for Extraterrestrial Physics
Masao Saito
The Graduate University for Advanced Studies (SOKENDAI)
National Institutes of Natural Sciences
Zhi-Yun Li
University of Virginia
Kazuhito Dobashi
Tokyo Gakugei University
Tomomi Shimoikura
Otsuma Women's University
Fumitaka Nakamura
The Graduate University for Advanced Studies (SOKENDAI)
National Institutes of Natural Sciences
University of Tokyo
Jonathan Tan
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
University of Virginia
Eric Herbst
University of Virginia
Astrophysical Journal, Supplement Series
0067-0049 (ISSN) 1538-4365 (eISSN)
Vol. 267 1 4Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Geochemistry
DOI
10.3847/1538-4365/acd110