The type IIb SN 2008ax: the nature of the progenitor
Gal-Yam, A.; Smartt, S. J.; Maund, J. R.; Kasliwal, M. M.; Fox, D. B.; Leonard, D. C.; Mattila, S.; Eldridge, J. J.; Danziger, I. J.; Crockett, R. M.; Pastorello, A.; Stephens, A. W.
United Kingdom, Israel, United States, Finland, Italy
Abstract
A source coincident with the position of the type IIb supernova (SN) 2008ax is identified in pre-explosion Hubble Space Telescope (HST) Wide Field Planetary Camera 2 observations in three optical filters. We identify and constrain two possible progenitor systems: (i) a single massive star that lost most of its hydrogen envelope through radiatively driven mass-loss processes, prior to exploding as a helium-rich Wolf-Rayet star with a residual hydrogen envelope, and (ii) an interacting binary in a low-mass cluster producing a stripped progenitor. Late time, high-resolution observations along with detailed modelling of the SN will be required to reveal the true nature of this progenitor star.