Hertzsprung gap stars in nearby galaxies and the quest for luminous red nova progenitors Hugo Tranin, Nadejda Blagorodnova, Viraj Karambelkar, Paul J. Groot, Steven Bloemen, Paul M. Vreeswijk, Daniëlle L. A. Pieterse and Jan van Roestel A&A, 695 (2025) A226 Published online: 20 March 2025 DOI: 10.1051/0004-6361/202452286