G11.2-0.3: The remains of a massive star that exploded, perhaps being witnessed by Chinese astronomers in 386 A.D.
Caption: G11.2-0.3 is a circularly symmetric supernova remnant that
contains a dense, rotating dead star at its center, representing a
textbook case of what the remnant of an exploding star should look like
after a couple thousand years. In Chandra's X-ray image, the pulsar and
a cigar-shaped cloud of energetic particles, known as a pulsar wind
nebula, are predominantly seen as high-energy X-rays (blue). A shell
of heated gas from the outer layers of the exploded star surrounds the
pulsar and the pulsar wind nebula and emits lower-energy X-rays
(represented in green and red).
Scale: Image is 8.4 arcmin across.
Chandra X-ray Observatory ACIS Image