Understanding the presence and distribution of prebiotic precursors in the interstellar medium (ISM) is key to tracing the chemical origins of life. Among them, 4-oxobutanenitrile (HCOCH2CH2CN) has been identified in laboratory simulations as a plausible intermediate in the formation of glutamic acid, a proteinogenic amino acid.
Here, we report its gas-phase rotational spectrum, measured using two complementary techniques: chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy (2ā18 GHz) and free-jet millimeter-wave (FJāAMMW) absorption spectroscopy (59.6ā80 GHz).
Quantum chemical calculations revealed nine low-energy conformers, of which the TC conformer was assigned based on the measured spectra. The resulting spectroscopic parameters were used to search for the molecule in the ultradeep spectral survey of the G+0.693-0.027 molecular cloud, located in the Galactic Center.
No signal attributable to 4āoxobutanenitrile was detected. A stringent upper limit to its column density was derived (N< 4 Ć1012 cmā2), corresponding to a molecular abundance of < 2.9 Ć10ā11 relative to H2.
This upper limit lies well below the observed abundances of simpler structurally related species containing āHCO and āCN groups, underscoring the challenge of detecting increasingly complex prebiotic molecules in the ISM and the need for future, more sensitive astronomical facilities.
V. M. Rivilla, E. R. Alonso, W. Song, A. Insausti, A. Maris, F. J. Basterretxea, S. Melandri, I. JimƩnez-Serra, E. J. Cocinero
Comments: Accepted in Monthly Notices of the Royal Astronomical Society
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2512.11500 [astro-ph.GA] (or arXiv:2512.11500v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2512.11500
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Submission history
From: Victor Manuel Rivilla
[v1] Fri, 12 Dec 2025 11:52:59 UTC (3,841 KB)
https://arxiv.org/abs/2512.11500
Astrobiology, Astrochemistry,
