Mon. Not. R. Astron. Soc., 436, 774-795 (2013/November-3)
The death of massive stars - II. Observational constraints on the progenitors of type Ibc supernovae.
ELDRIDGE J.J., FRASER M., SMARTT S.J., MAUND J.R. and CROCKETT R.M.
Abstract (from CDS):
The progenitors of many Type II core-collapse supernovae (SNe) have now been identified directly on pre-discovery imaging. Here, we present an extensive search for the progenitors of Type Ibc SNe in all available pre-discovery imaging since 1998. There are 12 Type Ibc SNe with no detections of progenitors in either deep ground-based or Hubble Space Telescope archival imaging. The deepest absolute BVR magnitude limits are between -4 and - 5mag. We compare these limits with the observed Wolf-Rayet population in the Large Magellanic Cloud and estimate a 16 percent probability that we have failed to detect such a progenitor by chance. Alternatively, the progenitors evolve significantly before core-collapse or we have underestimated the extinction towards the progenitors. Reviewing the relative rates and ejecta mass estimates from light-curve modelling of Ibc SNe, we find both incompatible with Wolf-Rayet stars with initial masses >25M☉ being the only progenitors. We present binary evolution models that fit these observational constraints. Stars in binaries with initial masses ≲ 20M☉ lose their hydrogen envelopes in binary interactions to become low-mass helium stars. They retain a low-mass hydrogen envelope until ~104yr before core-collapse; hence, it is not surprising that Galactic analogues have been difficult to identify.