... Keplers Supernova Remnant in X Rays . ... Some type of star exploded to create the unusually shaped nebula known as Kepler's supernova remnant , but which type? ... Recent X-ray data and images of Kepler's supernova remnant taken by the orbiting Chandra X-ray Observatory has shown relative elemental abundances more typical of a Type Ia supernova , indicating that the progenitor was a white dwarf star that exploded when it accreted too much material and went over Chandrasekhar's limit . ...