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 data were recorded with very high resolution which resolves, at least in part, the complex velocity structure and the ¹⁴N hyperfine structure splitting 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).

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