2000/03/06 by K. Nomoto, P. A. Mazzali, Nomoto, K. +18
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Nuclear Physics and Applications #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0003077
To be published in "Supernovae and Gamma Ray Bursts" ed. M. Livio et al. (Cambridge University Press), Corrections to references
openalex publication_date 2000/03/06 · arxiv created 2000/04/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We discuss the properties of the hyper-energetic Type Ic supernovae (SNe Ic) 1998bw and 1997ef and Type IIn supernova (SN IIn) 1997cy. SNe Ic 1998bw and 1997ef are characterized by their large luminosity and the very broad spectral features. Their observed properties can be explained if they are very energetic SN explosions with the kinetic energy of E\rm K \gsim 1×1052 erg, originating probably from the core collapse of the bare C+O cores of massive stars (∼ 30-40M_\odot). At late times, both the light curves and the spectra suggest that the explosions may have been asymmetric; this may help us understand the claimed connection with GRB's. The Type IIn SN 1997cy is even more luminous than SN 1998bw and the light curve declines more slowly than 56Co decay. We model such a light curve with circumstellar interaction, which requires the explosion energy of ∼ 5 × 1052 erg. Because these kinetic energies of explosion are much larger than in normal core-collapse SNe, we call objects like these SNe "hypernovae". The mass of 56Ni in SN 1998bw is estimated to be as large as 0.5 - 0.7 M_\odot from both the maximum brightness and late time emission spectra, which suggests that the asymmetry may not be extreme.