title: Detection of a red supergiant progenitor star of a type II-plateau supernova.
abstract: 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 that is a red supergiant of 8(+4)(-2) solar masses. This confirms both stellar evolution models and supernova theories predicting that cool red supergiants are the immediate progenitor stars of type II-plateau supernovae.
authors.affiliation: Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK. sjs@ast.cam.ac.uk
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Smartt
authors.forename: Justyn R
authors.initials: JR
authors.lastname: Maund
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Hendry
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Tout
authors.forename: Gerard F
authors.initials: GF
authors.lastname: Gilmore
authors.forename: Seppo
authors.initials: S
authors.lastname: Mattila
authors.forename: Chris R
authors.initials: CR
authors.lastname: Benn