===== On HCxN+ in the ISM ===== J. Cernicharo, C. Cabezas, M. Agúndez, Y. Endo, B. Tercero, N. Marcelino and P. de Vicente\\ reported on the\\ **[[https://doi.org/10.1051/0004-6361/202450801|QUIJOTE discovery of the cation radicals HC5N+ and HC7N+]]**\\ //Astron. Astrophys.// **686**, Art. No. L15 (2024).\\ HC₅N⁺ and HC₇N⁺ were identified through 7 and 8 unblended or slightly blended transitions in their ²Π_3/2 lower spin ladder, respectively, with 23/2 ≤ //J// ≤ 37/2 in the first case and 53/2 ≤ //J// ≤ 69/2 in the latter. The identifications were made in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope between 31.0 and 50.3 GHz. //T//_rot = 8.5 ± 0.5 K was derived for HC₅N⁺, while //T//_rot = 7.8 ± 0.1 K was derived for HC₇N⁺. The abundance ratios present a consistent and interesting picture. The HC₅N⁺ / HC₇N⁺ ratio is ~4.2; the HC₅N⁺ / HC₅N, HC₅N⁺ / C₅N⁻, and HC₅N⁺ / C₅N⁻ ratios are about 670, 4.8, and 1.2, respectively, while the HC₇N⁺ / HC₇N and HC₇N⁺ / C₇N⁻ ratios are about 1000 and 2.2, respectively.\\ \\ Shortly thereafter,\\ C. Cabezas, M. Agúndez, Y. Endo, B. Tercero, N. Marcelino, P. de Vicente, and J. Cernicharo\\ published on the\\ **[[https://doi.org/10.1051/0004-6361/202451081|Discovery of the interstellar cyanoacetylene radical cation HC3N+]]**\\ //Astron. Astrophys.// **687**, Art. No. L22 (2024).\\ The QUIJOTE survey of TMC-1 was employed once more to identify the six strong hyperfine structure components of the //J// = 7/2 − 5/2 near 31.63 GHz and 9/2 − 7/2 near 40.66 GHz in its ²Π_3/2 lower spin ladder with good signal-to-noise ratio. The HFS components where not or only slightly blended with the exception of one in the upper transition. Supporting, but less favorable results were presented for the 11/2 − 9/2 transition near 49.965 GHz. The rotational temperature was estimated to be 4.5 K. The HC₃N to HC₃N⁺ ratio is about 3200; the C₃N to HC₃N⁺ ratio about 300; the HC₃N⁺ to HC₅N⁺ ratio is about 0.6.\\ \\ ---- Contributor(s): H. S. P. Müller; 06, 2024; 07, 2024 ----