Detection of a red supergiant progenitor star of a type II-plateau   supernova
  We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion and subsequent HST images confirm the positional coincidence of the supernova with a single,resolved star which is an 8 +4/-2 solar mass red supergiant. This confirms both stellar evolution models and supernova theories which predict that type II-Plateau supernovae have cool red supergiants as their immediate progenitor stars. 
S. J. Smartt, J. R. Maund, M. A. Hendry, C. A. Tout, G. F. Gilmore   (IoA, Cambridge), S. Mattila (Stockholm Obs.), C. R. Be...