V. M. Rivilla, I. Jiménez-Serra, J. García de la Concepción, J. Martín-Pintado, L. Colzi, L. F. Rodríguez-Almeida, B. Tercero, F. Rico-Villas, S. Zeng, S. Martín, M. A. Requena-Torres, and P. de Vicente
reported on
Detection of the Cyanomidyl Radical (HNCN): a new Interstellar Species with the NCN Backbone
Mon. Not. R. Astron. Soc. Lett. 506, L79 − L84 (2021).
The cyanoamidogen radical, HNCN, was identified in the course of a molecular line survey of the Galactic center cold molecular cloud G+0.693−0.027 carried out with the Yebes 40 m and IRAM 30 m radio telescopes. Transitions (N + 1) → N with and K_a = 0 and N = 1 and 3 to 6 were covered. The two fine structure (FS) components of the N = 5 transition and possibly the J = 2.5 FS component of the N = 3 transition are unblended. The J = 3.3 FS component of the N = 4 transition is slightly blended, and the astronomical feature is modeled well. All other covered lines are blended more severely. The detection is probably fairly secure because of the low rotational temperature of ~9 K desite the somewhat small number of unblended or slightly blended lines. Nevertheless, some caution may be advised. The N = 7 transition was barely missed, but it may already be too weak. The N = 2 transition is probably not observable from the ground. The N = 1 transition is likely again weak, possibly even more so because of potentially resolvable ¹H or ¹⁴N hyperfine structure. The column density is about a factor of 22 lower than that of H₂NCN.

Contributor(s): H. S. P. Müller; 08, 2021