G299.2-2.9: A supernova remnant located about 16,000 light years from Earth.
Caption: This composite image shows G299.2-2.9 in X-ray light from Chandra (orange) that has been overlaid on an infrared image from the Two Micron All-Sky Survey (2MASS). Evidence points to G299.2-2.9 being the remains of a Type Ia supernova, where a white dwarf has grown sufficiently massive to cause a thermonuclear explosion. Because it is older than most supernova remnants caused by these explosions, at an age of about 4,500 years, G299.2-2.9 provides astronomers with an excellent opportunity to study how such remnants evolve over time.
Scale: Image is about
24 arcmin across (about 114 light years)
Chandra X-ray Observatory