First Mapping Of Prebiotic Molecule CH2NH In A Pre-stellar Core

We present the first spatially resolved map of methanimine CH₂NH in the prestellar core L1544 using the IRAM 30m telescope.

The 20,2-10,1 line at 127 GHz was mapped with 20″ resolution (∼2800 au), revealing extended CH₂NH emission across the core. The peak line intensity coincides with the well-known c-C₃H₂ peak, while the integrated intensity peaks between the HNCO and dust continuum peaks due to broader linewidths in the latter region.

Column densities of CH₂NH are ∼(0.5-1.4×)10¹² cm⁻², corresponding to fractional abundances of 5×10⁻¹¹-1×10⁻¹⁰, with a trend decreasing from the southern, carbon-chain rich region to the dust and HNCO peak in the north.

Comparison with complementary molecular maps and the gas-grain chemical model of Sipilä et al. suggests that neutral-neutral gas-phase reactions and dissociative recombination dominate in the outer carbon-chain shell. This study demonstrates that CH₂NH, a simple nitrogen- and carbon-bearing molecule previously detected with pointed observations in other cold cores, is present and spatially extended in the evolved pre-stellar core L1544.

This indicates that prebiotic nitrogen-carbon chemistry continues efficiently up to the onset of gravitational collapse, providing key constraints for astrochemical models and the early stages of chemical complexity leading to amino acids.

Yuxin Lin, Silvia Spezzano, Olli Sipilä, Jaime E. Pineda, Paola Caselli

Comments: Accepted by ApJL
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2512.12396 [astro-ph.GA] (or arXiv:2512.12396v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2512.12396
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Submission history
From: Yuxin Lin
[v1] Sat, 13 Dec 2025 17:06:06 UTC (765 KB)
https://arxiv.org/abs/2512.12396

Astrobiology, Astrochemistry,