BOLOMETRIC LIGHT CURVES OF SUPERNOVAE AND POSTEXPLOSION MAGNETIC-FIELDS

The various effects leading to diversity in the bolometric light curve s of supernovae are examined; nucleosynthesis, kinematic differences, ejected mass, degree of mixing, and configuration and intensity of the magnetic field are discussed. In Type Ia supernovae, a departure in t he bolometric light curve from the full-trapping decline of Co-56 can occur within the 2.5 years after the explosion, depending on the evolu tionary path followed by the white dwarf (WD) during the accretion pha se. If convection has developed in the WD core during the presupernova evolution, starting several thousand years before the explosion, a ta ngled magnetic held close to the equipartition value should have grown in the WD. Such an intense magnetic field would confine positrons whe re they originate from the Co-56 decays and preclude a strong departur e from the full-trapping decline as the supernova expands. This situat ion is expected to occur in C + O Chandrasekhar WDs as opposed to edge -lit detonated sub-Chandrasekhar WDs. If the preexplosion magnetic fie ld of the WD is less intense than 10(5)-10(8) G, a lack of confinement of the positrons emitted in the Co-56 decay and a departure from full trapping of their energy would occur. The time at which the departure takes place can provide estimates of the original magnetic field of t he WD, its configuration, and also of the mass of the supernova ejecta . In SN 1991BG, the bolometric light curve suggests an absence of a si gnificant tangled magnetic field: its intensity is estimated to be low er than 10(3) G. Chandrasekhar-mass models do not reproduce the bolome tric light curve of this supernova. For SN 1972E, on the contrary, the re is evidence for a tangled configuration of the magnetic field and i ts light curve is well reproduced by a Chandrasekhar WD explosion. A c omparison is made for the diagram of absolute magnitude and rate of de cline in Type Ia supernovae coming from different explosion mechanisms . The effects of mixing and ejected mass in the bolometric light curve of Type Ib, Ic supernovae are also discussed.