Kepler's Supernova Remnant in X-Rays.

What caused this mess? Some type of star exploded to create the unusually shaped nebula known as Kepler's supernova remnant , but which type? Light from the stellar explosion that created this energized cosmic cloud was first seen on planet Earth in October 1604, a mere four hundred years ago . The supernova produced a bright new star in early 17th century skies within the constellation Ophiuchus. It was studied by astronomer Johannes Kepler and his contemporaries, without the benefit of a telescope, as they searched for an explanation of the heavenly apparition. Armed with a modern understanding of stellar evolution , early 21st century astronomers continue to explore the expanding debris cloud, but can now use orbiting space telescopes to survey Kepler's supernova remnant (SNR) across the spectrum . Recent X-ray data and images of Kepler's supernova remnant taken by the orbiting Chandra X-ray Observatory has shown relative elemental abundances typical of a Type Ia supernova , and further indicated that the progenitor was a white dwarf star that exploded when it accreted too much material from a companion Red Giant star and went over Chandrasekhar's limit . About 13,000 light years away, Kepler's supernova represents the most recent stellar explosion seen to occur within our Milky Way galaxy.