Reddening, Abundances, and Line Formation in SNe II

We present detailed NLTE spectral synthesis models of the Type II supernova 2005cs, which occurred in M51 and for which the explosion time is well determined. We show that previous estimates for the reddening were significantly too high and briefly discuss how this will affect the inferred progenitor mass. We also show that standard CNO-burning-enhanced abundances require far too large an oxygen depletion, although there is evidence for a single optical N II line, and the sodium abundance shows clear evidence for enhancement over solar, both as expected from CNO processing. Finally, we calculate a distance using the SEAM method. Given the broad range of distances to M51 in the literature, the determination of a distance using Cepheid variables would be quite valuable.