Chemical Differentiation around Five Massive Protostars Revealed by ALMA -Carbon-Chain Species, Oxygen-/Nitrogen-Bearing Complex Organic Molecules
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.
Kotomi Taniguchi, Liton Majumdar, Paola Caselli, Shigehisa Takakuwa, Tien-Hao Hsieh, Masao Saito, Zhi-Yun Li, Kazuhito Dobashi, Tomomi Shimoikura, Fumitaka Nakamura, Jonathan C. Tan, Eric Herbst
Comments: Accepted by the publication for The Astrophysical Journal Supplement Series, 32 pages,18 figures, 11 tables
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2304.13873 [astro-ph.GA] (or arXiv:2304.13873v1 [astro-ph.GA] for this version)
Submission history
From: Kotomi Taniguchi Dr.
[v1] Wed, 26 Apr 2023 23:40:28 UTC (25,585 KB)
https://arxiv.org/abs/2304.13873
Astrobiology, Astrochemistry
