|Annu. Rev. Astron. Astrophys. 1998. 36:
Copyright © 1998 by . All rights reserved
SNe Ia appear to be carbon ignitors. If normal SNe Ia are Chandrasekhar-mass explosions in single-degenerate progenitor systems, their light curves and spectra indicate that they eject MNi 0.6 M. If they are mergers of double degenerates, they should be at least mildly super-Chandrasekhar and then should eject somewhat more 56Ni to achieve the temperature needed to account for their spectra.