Digging Into The Interior Of Hot Cores With ALMA (DIHCA). III: The Chemical Link Between NH2CHO, HNCO, And H2CO

By Keith Cowing
Press Release
April 4, 2023
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Digging Into The Interior Of Hot Cores With ALMA (DIHCA). III: The Chemical Link Between NH2CHO, HNCO, And H2CO
Continuum images (gray scales) overlaid with contours indicating moment 0 maps of molecular lines (left panel: white; CH3CN and cyan; H2CO, right panel: magenta; NH2CHO and yellow; HNCO) toward G10.62-0.38. Red crosses indicate the positions of hot molecular cores (HMCs) identified based on moment 0 maps of the CH3CN line. Information on noise levels and contour levels are summarized in Tables 8 and 9. — astro-ph.SR)

We have analyzed the NH2CHO, HNCO, H2CO, and CH3CN (13CH3CN) molecular lines at an angular resolution of ∼0.3″ obtained by the Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 toward 30 high-mass star-forming regions. The NH2CHO emission has been detected in 23 regions, while the other species have been detected toward 29 regions.

A total of 44 hot molecular cores (HMCs) have been identified using the moment 0 maps of the CH3CN line. The fractional abundances of the four species have been derived at each HMC. In order to investigate pure chemical relationships, we have conducted a partial correlation test to exclude the effect of temperature. Strong positive correlations between NH2CHO and HNCO (ρ=0.89) and between NH2CHO and H2CO (0.84) have been found.

These strong correlations indicate their direct chemical links; dual-cyclic hydrogen addition and abstraction reactions between HNCO and NH2CHO and gas-phase formation of NH2CHO from H2CO. Chemical models including these reactions can reproduce the observed abundances in our target sources.

Kotomi Taniguchi, Patricio Sanhueza, Fernando A. Olguin, Prasanta Gorai, Ankan Das, Fumitaka Nakamura, Masao Saito, Qizhou Zhang, Xing Lu, Shanghuo Li, Huei-Ru Vivien Chen

Comments: Accepted for The Astrophysical Journal. 27 pages, 10 tables, and 13 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2304.00267 [astro-ph.GA] (or arXiv:2304.00267v1 [astro-ph.GA] for this version)
Submission history
From: Kotomi Taniguchi Dr.
[v1] Sat, 1 Apr 2023 09:16:18 UTC (9,669 KB)
Astrobiology, Astrochemistry

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