The white dwarf’s carbon fraction as a secondary parameter of Type Ia supernovae Sebastian T. Ohlmann, Markus Kromer, Michael Fink, Rüdiger Pakmor, Ivo R. Seitenzahl, Stuart A. Sim and Friedrich K. Röpke A&A, 572 (2014) A57 Published online: 27 November 2014 DOI: 10.1051/0004-6361/201423924