Rutgers Departmental Colloquia

The explosions of supernovae of Type Ia play a significant role in diverse areas of astrophysics. Their high peak luminosities, together with an observed correlation of the peak brightness with the width of the light curve, make possible their effective use as probes of the distance scale of the Universe. This has led to our realization that the rate of expansion of the Universe is accelerating. The burning of approximately 0.8 solar masses 12C and 16O to iron-peak nuclei (predominantly 56Ni) in the explosive ejection of their progenitor white dwarf cores provides 1/2 to 2/3 of the abundance of 56Fe in our Galaxy and the Universe. Abundance determinations for the stellar components of our Galaxy together with those for forming galaxies at high redshifts reveal interesting elemental abundance patterns, reflecting distinctive contributions from Type Ia and Type II supernova events. We review the calculated behaviors of SNe Ia explosions as revealed in recent numerical models, the critical dependences of their outburst characteristics upon nuclear energetics, their predictions for nucleosynthesis, possible dependences of their outburst characteristics upon their initial compositions, their significance for cosmology, and their contributions to cosmic chemical evolution. We then briefly identify and explore some implications of the delayed entry of the nuclear products of SNe Ia, relative to those of SNe II, into the interstellar media of galaxies and the constraints this imposes upon the early star formation and nucleosynthesis histories of galaxies and the Cosmos.