![Gas-phase abundance evolution of CH3OH, CH3CHO, CH3OCHO, and CH3OCH3 in the representative warm-up model with Tmax = 200 K. The shaded rectangles indicate the observed abundance ranges derived in this work. The gray vertical band marks the time interval, (1.25–1.42) × 106 yr, over which the model abundances overlap most closely with the observed ranges for the four species. -- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Molecule-dependent.png?fit=1200%2C677&ssl=1)
[astro-ph.GA] We present a uniform IRAM-30m survey analysis of four oxygen-bearing complex organic molecules (COMs), methanol (CH3OH), acetaldehyde (CH3CHO), methyl formate (CH3OCHO), and dimethyl ether (CH3OCH3), toward 50 high-mass star-forming regions (HMSFRs) associated with 6.7GHz methanol masers.
Column densities were derived through a homogeneous rotation-diagram approach, with CH3CN used as a proxy excitation-temperature reference when needed. In CH3OH-normalized abundance-ratio space, CH3OCHO/CH3OH and CH3OCH3/CH3OH show the strongest pairwise correlation, whereas the correlations involving CH3CHO are weaker.
No clear monotonic trends are found with Galactocentric distance or beam-averaged H2 column density. Comparison with previous observations places the CH3OCHO–CH3OCH3 behavior within the range of earlier abundance-ratio measurements, while CH3CHO shows larger inter-study variation.
A representative warm-up chemical model is used only for qualitative comparison with the observed abundance ranges, which are most closely matched during the decline from the post-desorption abundance peaks in the model.
These results provide homogeneous beam-averaged abundance-ratio constraints for common O-bearing COMs in high-mass star-forming regions and show that their source-to-source behavior is molecule-dependent rather than fully described by a single common abundance pattern.
Xuefang Xu, Mingwei He, Qian Gou, Jiao He, Junzhi Wang, Donghui Quan, Di Li, Laurent Pagani, Juan Li, Guoming Zhao, Chunguo Duan, Yang Lu, Luyao Zou
Comments: 9 pages, 6 figures, 3 tables, accepted for publication in A&A
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2607.16734 [astro-ph.GA] (or arXiv:2607.16734v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2607.16734
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Submission history
From: Xuefang Xu
[v1] Sat, 18 Jul 2026 09:47:38 UTC (2,995 KB)
https://arxiv.org/abs/2607.16734
Astrobiology, Astrochemistry, Interstellar,
