The type Ic hypernova SN 2002ap Original Research Article

We investigate the properties of the Type Ic supernova (SN) 2002ap through models of its spectral evolution and light curve (LC). Its spectra are similar to those of the “hypernova” SN 1997ef, showing unusually broad O i, Ca ii, Si ii and Fe ii P Cygni lines. However, its kinetiv energy [∼ (4 – 10) × 1051 ergs], and the mass ejected (2.5 – 5 M⊙) are smaller, resulting in faster evolving LCs and spectra. About 0.07 M⊙56Ni is required for its peak luminosity, some of which were mixed to the outer layer. We suggest that SN 2002ap, lying at the low-energy and low-mass end of the hypernova sequence, is likely the explosion of a 5 M⊙ C+O star, corresponding to a main sequence mass 20 – 25 M⊙.