Double-detonation sub-Chandrasekhar supernovae: can minimum helium shell masses detonate the core? M. Fink, F. K. Röpke, W. Hillebrandt, I. R. Seitenzahl, S. A. Sim and M. Kromer A&A, 514 (2010) A53 Published online: 19 May 2010 DOI: 10.1051/0004-6361/200913892