Detection And Prebiotic Chemistry of Possible Glycine Precursor Molecule Methylenimine Towards The Hot Molecular Core G10.47+0.03

By Keith Cowing
Status Report
April 19, 2024
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Detection And Prebiotic Chemistry of Possible Glycine Precursor Molecule Methylenimine Towards The Hot Molecular Core G10.47+0.03
Integrated emission maps of detected transitions of CH2NH towards the G10.47+0.03, which are overlaid with the 2.34 mm continuum emission map. The contour levels are 20%, 40%, 60%, and 80% of peak flux. The cyan circle represents the synthesized beam of the integrated emission maps. — astro-ph.GA

Amino acids are essential for the synthesis of protein. Amino acids contain both amine (R−NH2) and carboxylic acid (R−COOH) functional groups, which help to understand the possible formation mechanism of life in the universe.

Among the 20 types of amino acids, glycine (NH2CH2COOH) is known as the simplest non-essential amino acid. In the last 40 years, all surveys of NH2CH2COOH in the interstellar medium, especially in the star-formation regions, have failed at the millimeter and sub-millimeter wavelengths. We aimed to identify the possible precursors of NH2CH2COOH, because it is highly challenging to identify NH2CH2COOH in the interstellar medium.

Many laboratory experiments have suggested that methylenimine (CH2NH) plays a key role as a possible precursor of NH2CH2COOH in the star-formation regions via the Strecker synthesis reaction. After spectral analysis using the local thermodynamic equilibrium (LTE) model, we successfully identified the rotational emission lines of CH2NH towards the hot molecular core G10.47+0.03 using the Atacama Compact Array (ACA). The estimated column density of CH2NH towards G10.47+0.03 is (3.40±0.2)×1015 cm−2 with a rotational temperature of 218.70±20 K, which is estimated from the rotational diagram.

The fractional abundance of CH2NH with respect to H2 towards G10.47+0.03 is 2.61×10−8. We found that the derived abundance of CH2NH agree fairly well with the existing two-phase warm-up chemical modelling abundance value of CH2NH. We discuss the possible formation pathways of CH2NH within the context of hot molecular cores, and we find that CH2NH is likely mainly formed via neutral-neutral gas-phase reactions of CH3 and NH radicals towards G10.47+0.03.

Proposed possible formation mechanism of CH2NH and NH2CH2COOH. In the chemical diagram, the black/grey dumbbell indicates the carbon (C) atom, the white dumbbell indicates the hydrogen (H) atom, the blue dumbbell indicates the nitrogen (N) atom, and the red dumbbell indicates the oxygen (O) atom. In the chemical reaction, “H2O” represents the hydrolysis process. References: (A) Woon et al. (2002); Theule et al. (2011); (B) Danger et al. (2011); (C) Alonso et al. (2018). — astro-ph.GA

Arijit Manna, Sabyasachi Pal

Comments: Accepted for publication in International Journal of Astrobiology. arXiv admin note: text overlap with arXiv:2402.16798
Subjects: Astrophysics of Galaxies (astro-ph.GA); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2404.12212 [astro-ph.GA] (or arXiv:2404.12212v1 [astro-ph.GA] for this version)
Submission history
From: Arijit Manna
[v1] Thu, 18 Apr 2024 14:17:21 UTC (562 KB)
Astrobiology, Astrochemistry,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻