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

Homi Bhabha National Institute (HBNI)

National Institute of Science Education and Research

Paola Caselli

Max Planck Society

Shigehisa Takakuwa

Academia Sinica

Kagoshima University

Tien-Hao Hsieh

Max Planck Society

Masao Saito

National Institutes of Natural Sciences

The Graduate University for Advanced Studies (SOKENDAI)

Zhi-Yun Li

University of Virginia

Kazuhito Dobashi

Tokyo Gakugei University

Tomomi Shimoikura

Otsuma Women's University

Fumitaka Nakamura

University of Tokyo

National Institutes of Natural Sciences

The Graduate University for Advanced Studies (SOKENDAI)

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 4

Subject Categories (SSIF 2011)

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Geochemistry

DOI

10.3847/1538-4365/acd110

More information

Latest update

3/16/2025