The current classification scheme for supernovae is presented. The main observational features of the supernova types are described and the physical implications briefly addressed. Differences between the homogeneous thermonuclear type Ia and similarities among the heterogeneous core collapse type Ib, Ic and II are highlighted. Transforming type IIb, narrow line type IIn, supernovae associated ...

We propose a bipolar jet model for supernova polarization. Light from the main component of the supernova (which we call the bulk supernova for short) scatters off electrons in the jets and is polarized: this polarized light is added to the direct emission from the bulk supernova and causes the overall supernova emission to be polarized. The motivation for the bipolar jet model is to resolve th...

Recent evidence on the metal content of the high-redshift Lyα forest seen in quasar spectra suggests that an early generation of galaxies enriched the intergalactic medium (IGM) at z ∼ > 5. We calculate the number of supernovae that need to have taken place to produce the observed metallicity. The progenitor stars of the supernovae should have emitted ∼ 20 ionizing photons for each baryon in th...

We present the first unambiguous detection of helium emission lines in spectra of Type Ic supernovae (SNe Ic). The presence of He I lines, with full width at half maximum ≈ 2000 km s, and the distinct absence of any other intermediate-width emission (e.g., Hα), implies that the ejecta of SN Ic 1999cq are interacting with dense circumstellar material composed of almost pure helium. This strength...

A simple description of core-collapse supernovae is given. Properties of the neutrino-driven wind, neutrino fluxes and luminosities, reaction rates, and the equilibrium electron fraction in supernova environments are discussed. Neutrino mixing and neutrino interactions that are relevant to core-collapse supernovae are briefly reviewed. The values of electron fraction under several evolution sce...

We briefly describe the current version of the PHOENIX code. We then present some results on the modeling of Type II supernovae and show that fits to observations can be obtained, when account is taken for spherically symmetric, line-blanketed, expanding atmospheres. We describe the SEAM method of obtaining distances to supernovae and briefly discuss its future prospects.