RCW 86: Oldest Recorded Supernova
Shown in the image above is a multi-wavelength image of supernova remnant RCW 86. First witnessed by humanity in 185 A.D., the supernova was visible for eight months. The blue and green colors in the image were obtained by using x-ray images from NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton Observatory. The observations of X-rays show interstellar gas heated by the supernova’s shockwave.
The red and yellow colors in the image come from infrared data from NASA’s Spitzer Space Telescope, and Wide-Field Infrared Survey Explorer (WISE). The infrared data shows dust radiating at a temperature of several hundred degrees below zero, warm by comparison to normal dust in our Milky Way galaxy.
Combining the X-ray and infrared data allowed astronomers to better understand that the cause of the explosion was a Type Ia supernova. White dwarf stars that are normally stable can detonate into a type 1a supernova when a companion star dumps extra material onto the white dwarf’s surface. The combined data also allowed researchers to determine how the remnant expanded in a very short amount of time, cosmically speaking. Scientists believe that by blowing a powerful wind prior to exploding, the white dwarf was able to clear out a huge cavity. The cavity, being a region of low density would allow the supernova explosion to expand much faster than normal.
What makes this discovery interesting to astronomers is that it’s the first cavity detected around a white dwarf system prior to explosion. Scientists say the results may have significant implications for theories of white-dwarf binary systems and Type Ia supernovae.
RCW 86 is approximately 8,000 light-years away. At about 85 light-years in diameter, it occupies a region of the sky in the southern constellation of Circinus that is slightly larger than the full moon.
If you’d like to learn more about the Chandra X-ray observatory, visit: http://chandra.harvard.edu/about/