ENERGY DEPOSITION AND K-SHELL IONIZATION OF SUPERNOVAE

We present explicit evaluation of K-shell ionization caused by photoel ectric absorption, by Compton scattering, and by electron collisions i n supernovae envelopes. Each process derives from the radioactivity th at dominates the bolometric luminosity of the model supernovae. We inc lude the ionization by bremsstrahlung. We find that electron-collision ionization with decelerating Compton electrons is the dominant proces s of K-shell ionization for light elements (lighter than Si) whereas p hotoelectric K-shell absorption of Comptonized gammas is the dominant process of K-shell ionization for heavy elements (like Fe). The relati ve importance of the ionization processes also depends upon compositio n and upon time, as well as upon supernova type. For Type Ia all four ionization sources are of importance. We present fitting formulas for the deposition of radioactive power in each class of models studied. T he energy deposition of all mechanisms decreases with time, including the rate of K-shell ionizations of all elements throughout the superno vae model evaluated herein. We compare the relative contributions to t he energy deposition and confirm with greater numerical detail results already established.