2025/12/13 by Yuxin Lin, Lin, Yuxin, S. Spezzano +11 · 2 voices
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/2041-8213/ae2c76
arxiv published 2025/12/13 · arxiv updated 2025/12/13 · openalex publication_date 2026/01/06 · openalex created_date 2026/01/08 · openalex updated_date 2026/06/11
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.