Why hot horizontal branch stars can appear redder than red giants Y. Momany, S. Cassisi, G. Piotto, L. R. Bedin, S. Ortolani, F. Castelli and A. Recio-Blanco A&A, 407 1 (2003) 303-309 Published online: 17 November 2003 DOI: 10.1051/0004-6361:20030827