First Glycine Isomer Detected In The Interstellar Medium: Glycolamide (NH2C(O)CH2OH)
We report the first detection in the interstellar medium of a C2H5O2N isomer: syn-glycolamide (NH2C(O)CH2OH).
The exquisite sensitivity at sub-mK levels of an ultra-deep spectral survey carried out with the Yebes 40m and IRAM 30m telescopes towards the G+0.693-0.027 molecular cloud have allowed us to unambiguously identify multiple transitions of this species.
We derived a column density of (7.4 ± 0.7)×1012 cm−2, which implies a molecular abundance with respect to H2 of 5.5×10−11. The other C2H5O2N isomers, including the higher-energy anti conformer of glycolamide, and two conformers of glycine, were not detected. The upper limit derived for the abundance of glycine indicates that this amino acid is surely less abundant than its isomer glycolamide in the ISM. The abundances of the C2H5O2N isomers cannot be explained in terms of thermodynamic equilibrium, and thus chemical kinetics need to be invoked.
While the low abundance of glycine might not be surprising, based on the relative low abundances of acids in the ISM compared to other compounds (e.g. alcohols, aldehydes or amines), several chemical pathways can favour the formation of its isomer glycolamide. It can be formed through radical-radical reactions on the surface of dust grains. The abundances of these radicals can be significantly boosted in an environment affected by a strong ultraviolet field induced by cosmic rays, such as that expected in G+0.693-0.027.
Therefore, as shown by several recent molecular detections towards this molecular cloud, it stands out as the best target to discover new species with carbon, oxygen and nitrogen with increasing chemical complexity.
Víctor M. Rivilla, Miguel Sanz-Novo, Izaskun Jiménez-Serra, Jesús Martín-Pintado, Laura Colzi, Shaoshan Zeng, Andrés Megías, Álvaro López-Gallifa, Antonio Martínez-Henares, Sarah Massalkhi, Belén Tercero, Pablo de Vicente, Sergio Martín, David San Andríes, Miguel A. Requena-Torres, José Luis Alonso
Comments: Accepted in The Astrophysical Journal Letters
Subjects: Astrophysics of Galaxies (astro-ph.GA); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2307.11507 [astro-ph.GA] or arXiv:2307.11507v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2307.11507
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Submission history
From: Victor Manuel Rivilla
[v1] Fri, 21 Jul 2023 11:31:53 UTC (2,828 KB)
https://arxiv.org/abs/2307.11507
Astrobiology, Astrochemistry
