Kepler’s Supernova Remnant
NASA’s Chandra X-ray Observatory has enabled scientists to better understand a mystery which has endured for over 400 years. Johannes Kepler, renowned astronomer, and other star-gazers noticed a new object in the sky, initially shining brighter than Jupiter. The unaided eye was the only means of observing the sky at the time so it was not known what the object was as it dimmed over the subsequent weeks. The origin of the object, which became known as Kepler’s supernova remnant, remained undiscovered. Although astronomers used radio, optical and x-ray telescopes intensively to study the remnant, it wasn’t until the Chandra Observatory provided the latest x-ray images that enabled astronomers to use combined observations over a period of nine days, in order to create a detailed image of one of the brightest supernovas recorded in the Milky Way galaxy.
The remains of the exploding star that left the Kepler remnant were ejected into space, heating gases to millions of degrees, creating high-energy particles and generating large amounts of x-ray energy, typical of supernovas. The supernova’s origin was unknown because the presence of large amounts of iron and no apparent neutron star in the vicinity indicated a type Ia supernova, created when a white dwarf star attracts material from another star orbiting around it until the white dwarf becomes unstable and is destroyed in a thermonuclear explosion. However, optical light reveals what appears to be the remnant expanding into dense nitrogen-rich material, suggesting a “Type II” supernova, created by the collapse of a single massive star which ejects material before exploding, conditions not typical of a Type Ia supernova. The data obtained from Chandra was used to compare the relative amounts of oxygen and iron in the supernova, indicating that Kepler was the result of a Type Ia event.
It has been suggested that the dense material in the remnant could be an indication that it is the closest example of a comparatively rare “prompt” Type Ia supernova which, in the more massive stars, explode only about 100 million years after their formation instead of the usual several billion. If so, Kepler could provide new information about how “prompt” explosions involving massive stars differ from the more typical supernovas. Also, Type Ia stars are used as standards for studies of dark energy, and new information would increase their reliability for this purpose, as well as aid in understanding the role of these stars in the formation of most of the iron in the universe.
This entry was posted on Monday, July 16th, 2007 at 6:27 am and is filed under Space Agency News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
