===== On Extragalactic Protonated Acetylene ===== S. Muller, R. Le Gal, E. Roueff, J. H. Black, A. Faure, M. Guélin, A. Omont, M. Gérin, F. Combes, and S. Aalto\\ reported on the\\ **[[https://doi.org/10.1051/0004-6361/202348994|Protonated Acetylene in the //z// = 0.89 Molecular Absorber toward PKS 1830−211]]**\\ //Astron. Astrophys.// **683**, (2024) Art. No. A62.\\ \\ The molecule C₂H₃⁺ was identified through the //ortho//-transition 2₁₂ – 1₀₁ at a rest frequency of 494.034 GHz and through the //para//-transition 1₁₁ – 0₀₀ at a rest frequency of 431.315 GHz. Protonated acetylene is less abundant than C₂H and C₄H by factors of about 600 and 60, respectively.\\ \\ ---- Contributor(s): H. S. P. Müller; 03, 2024 ----