===== On the Detection of Pentadiynylidynium, C₅H⁺, in Space ===== J. Cernicharo, M. Agúndez, C. Cabezas, R. Fuentetaja, B. Tercero, N. Marcelino, Y. Endo, J. R. Pardo, and P. de Vicente\\ reported on the\\ **[[https://doi.org/10.1051/0004-6361/202142992|Discovery of C₅H⁺ and Detection of C₃H⁺ in TMC-1 with the QUIJOTE Line Survey]]**,\\ //Astron. Astrophys.// **657**, Art. No. L16 (2022).\\ Pentadiynylidynium, C₅H⁺, was identified through four successive transitions, //J// = 7 − 6 near 33.8 GHz to //J// = 10 − 9 near 48.2 GHz, in the course of a line survey carried out with the 40 m Yebes radio telescope. The molecule is a factor of 3.7 ± 0.5 more abundant than C₃H⁺, which was explained by the reactivity of the latter with H₂ through chemical modeling.\\ ---- Contributor(s): H. S. P. Müller; 03, 2022 ----