This Chandra X-ray Observatory image shows the central region of the supernova remnant Cassiopeia A, the remains of a massive star that exploded in our galaxy. Evidence for a thin carbon atmosphere on a neutron star at the center of Cas A has been found. Besides resolving a ten-year-old mystery about the nature of this object, this result provides a vivid demonstration of the extreme nature of neutron stars. An artist's impression of the carbon-cloaked neutron star is also shown.
X-ray:NASA/CXC/Southampton/W. Ho et al.; Illustration: NASA/CXC/M.Weiss