We (Noam Soker, Enrique Garcia-Berro, and Leandro G. Althaus) argue that the properties of the Type Ia supernova SN 2011fe can be best explained within the frame of the core-degenerate (CD) scenario.
More: In the CD scenario a white dwarf (WD) merges with the core of an asymptotic giant branch (AGB) star and forms a rapidly rotating WD, with a mass close to and above the critical mass for explosion. Rapid rotation prevents immediate collapse and/or explosion. Spinning down over a time of 0-10 billion year brings the WD to explosion. A very long delayed explosion to post-crystallization phase, which lasts for about 2 billion years leads to the formation of a highly carbon-enriched outer layer. This can account for the carbon-rich composition of the fastest-moving ejecta of SN 2011fe. In reaching the conclusion that the CD scenario best explains the observed properties of SN 2011fe we consider both its specific properties, like a very compact exploding object and carbon rich composition of the fastest-moving ejecta, and the general properties of SNe Ia. The full paper is here.