The source of G1.9+0.3 was most likely a white dwarf star that underwent a thermonuclear detonation and was destroyed after merging with another white dwarf, or pulling material from an orbiting companion star. This is a particular class of supernova explosions (known as Type Ia) that are used as distance indicators in cosmology because they are so consistent in brightness and incredibly luminous. The explosion ejected stellar debris at high velocities, creating the supernova remnant that is seen today by Chandra and other telescopes. This new image is a composite from Chandra where low-energy X-rays are red, intermediate energies are green and higher-energy ones are blue. Also shown are optical data from the Digitized Sky Survey, with appearing stars in white. The Chandra data show that most of the X-ray emission is synchrotron radiation, produced by extremely energetic electrons accelerated in the rapidly expanding blast wave of the supernova. This emission gives information about the origin of cosmic rays, energetic particles that constantly strike the Earth's atmosphere, but not much information about Type Ia supernovas. In addition, some of the X-ray emission comes from elements produced in the supernova, providing clues to the nature of the explosion. The long Chandra observation was required to dig out those clues. Most Type Ia supernova remnants are symmetrical in shape, with debris evenly distributed in all directions. However, G1.9+0.3 exhibits an extremely asymmetric pattern. The strongest X-ray emission from elements like silicon, sulfur, and iron is found in the northern part of the remnant, giving an extremely asymmetric pattern. Release date June 26, 2013.