C. Xue, E. Willis, R. Loomis, K. Lee, A. Burkhardt, C. Shingledecker, S. Charnley, M. Cordiner, S. Kalenskii, M. McCarthy, E. Herbst, A. Remijan, and B. McGuire
reported on the
Detection of Interstellar HC₄NC and an Investigation of Isocyanopolyyne Chemistry under TMC-1 Conditions
Astrophys. J. Lett. 900, Art. No. L9 (2020).
The observations were obtained in the course of the line survey GOTHAM (Green Bank Telescope Observations of TMC-1: Hunting for Aromatic Molecules). The data were recorded with very high resolution which resolves, at least in part, the complex velocity structure and the ¹⁴N hyperfine structure splitting of the J = 8 → 7, 9 → 9, and 10 → 9 transitions near 22.4, 25.2, and 28.0 GHz, respectively, at the expense of noise levels of about the same level as the individual lines. The analysis was improved by employing a stacking technique. The HC₄NC to HC₄CN ratio is about 1 to 200, while the HC₂NC to HC₂CN ratio is about 1 to 50.

Almost at the same time,
J. Cernicharo, N. Marcelino, M. Agúndez, C. Bermúdez, C. Cabezas, B. Tercero, and J. R. Pardo
reported on the
Discovery of HC₄NC in TMC-1: A study of the isomers of HC₃N, HC₅N, and HC₇N
Astron. Astrophys. 642, Art. No. L8 (2020).
The observations were obtained with the Yebes 40m radio telescope in the course of a line survey covering 31.0–50.3 GHz and cover J“ = 11 to 15 of the molecule. The findings are compatible with the ones mentioned above.

Contributor(s): H. S. P. Müller; 10, 2020