2011MNRAS.412L..78Y

SN 2007bi is an extremely luminous Type Ic supernova. This supernova is thought to be evolved from a very massive star, and two possibilities have been proposed for the explosion mechanism. One possibility is a pair-instability supernova with an M_CO∼ 100 M_☉ CO core progenitor. Another possibility is a core-collapse supernova with M_CO∼ 40 M_☉. We investigate the evolution of very massive stars with main-sequence mass M_MS= 100-500 M_☉ and Z₀= 0.004, which is in the metallicity range of the host galaxy of SN 2007bi, to constrain the progenitor of SN 2007bi. The supernova type relating to the surface He abundance is also discussed. The main-sequence mass of the progenitor exploding as a pair-instability supernova could be M_MS∼ 515-575 M_☉. The minimum main-sequence mass could be 310 M_☉ when uncertainties in the mass-loss rate are considered. A star with M_MS∼ 110-280 M_☉ evolves to a CO star, appropriate for the core-collapse supernova of SN 2007bi. Arguments based on the probability of pair-instability and core-collapse supernovae favour the hypothesis that SN 2007bi originated from a core-collapse supernova event.