Advancements in radiative hydrodynamic simulations of early phases of Type II supernovae

Between the time when the shock approaches the outside of the progenitor star, when the shocked material is highly ionized, and a few months later, when the material has cooled and recombination is almost complete, details of the coupling of radiation and the hydrodynamics of the shock propagation may be significant, with a subsequent effect on the photosphere and thus spectra. This paper argues for the inadequacy of current analyses of shock breakout and of the customary adoption of self-similar expansion of an initial structure for spectral synthesis of the first few months, in place of a complete hydrodynamic simulation. Progress toward a full radiative hydrodynamic simulation including relativistic effects and detailed line opacities is discussed.