Chemistry and ro-vibrational excitation of HeH+ in the Planetary Nebula NGC 7027 M. Sil, A. Faure, H. Wiesemeyer, P. Hily-Blant, J. Loreau, K. D. Pérez, R. Čurík and F. Lique A&A, 695 (2025) A244 Published online: 25 March 2025 DOI: 10.1051/0004-6361/202453173