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Peculiar, low-luminosity Type II supernovae: low-energy explosions in massive progenitors?

2003; Oxford University Press; Volume: 338; Issue: 3 Linguagem: Inglês

10.1046/j.1365-8711.2003.06082.x

1365-2966

L. Zampieri, A. Pastorello, M. Turatto, E. Cappellaro, S. Benetti, G. Altavilla, P. A. Mazzali, M. Hamuy,

Astrophysical Phenomena and Observations

A number of supernovae, classified as Type II, show remarkably peculiar properties such as an extremely low expansion velocity and an extraordinarily small amount of 56Ni in the ejecta. We present a joint analysis of the available observations for two of these peculiar Type II supernovae, SN 1997D and SN 1999br, using a comprehensive semi-analytic method that can reproduce the light curve and the evolution of the line velocity and continuum temperature. We find that these events are underenergetic with respect to a typical Type II supernova and that the inferred mass of the ejecta is relatively large. We discuss the possibility that these supernovae originate from the explosion of a massive progenitor in which the rate of early infall of stellar material on the collapsed core is large. Events of this type could form a black hole remnant, giving rise to significant fallback and late-time accretion.