Este fue
tu cielo.

Cooling Neutron Star

Cassiopeia A, or Cas A, is a supernova remnant about 11,000 light-years away. The light from this massive star's death explosion reached Earth 330 years ago. The expanding debris cloud is about 15 light-years across, and at its center is a neutron star. This neutron star, the collapsed remains of the stellar core, is still hot enough to emit X-rays as it cools.