===== On the Detection of Methyleneamidogen, H2CN, in the ISM =====

M. Ohishi, D. McGonagle, W. M. Irvine, S. Yamamoto, and S. Saito\\
reported on the\\
**[[https://ui.adsabs.harvard.edu/abs/1994ApJ...427L..51O|Detection of a New Interstellar Molecule, H<sub>2</sub>CN]]**,\\
//Astrophys. J.// **427**, L51 (1994).\\
Two noisy features near 73.35 GHz, observed with the 12 m NRAO telescope at Kitt Peak, were assigned to <sup>1</sup>H hyperfine components of the 1<sub>01</sub> − 0<sub>00</sub> transition of H<sub>2</sub>CN. This identification was, however, refuted later, see comment on Cabezas et al. below. The authors also identify tentatively a line near 146.67 GHz observed toward Sgr B2(N) to a blend of three hyperfine components of the 2<sub>02</sub> − 1<sub>01</sub> transition of H<sub>2</sub>CN. This identification has not been substantiated thus far. If this latter identification were correct, our recent knowledge suggest that the molecule would then reside in the less dense envelope of Sgr B2(N).\\


C. Vastel, J. C. Loison, V. Wakelam, and B. Lefloch\\
reported on the\\
**[[https://doi.org/10.1051/0004-6361/201935010|Isocyanogen Formation in the Cold Interstellar Medium]]**,\\
//Astron. Astrophys.// **625**, art. no. A91 (2019).\\
A molecular line survey of the prestellar core L1544 between 71.74 and 115.87 GHz was carried out with the IRAM 30 m telescope. Methyleneamidogen was observed through six hyperfine transitions around 73.4 GHz.\\


C. Cabezas, M. Agúndez, N. Marcelino, B. Tercero, S. Cuadrado, and J. Cernicharo\\
reported on the\\
**[[https://doi.org/10.1051/0004-6361/202141491|Interstellar Detection of the Simplest Aminocarbyne H<sub>2</sub>NC: An ignored but Abundant Molecule]]**,\\
//Astron. Astrophys.// **654**, art. no. A45 (2021).\\
The authors give accounts on methyleneamidogen in the L483 and B1-b protostellar objects from earlier molecular line surveys carried out at 3 mm using the IRAM 30 m telescope; the L483 results were mentioned in an earlier publication, but only a column density was given. The molecule was **not** detected in corresponding data of the prestellar core TMC-1. The column densities of H<sub>2</sub>CN and H<sub>2</sub>NC were essentially the same in the first two sources.\\

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Contributor(s): H. S. P. Müller; 09, 2021; 10, 2021

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