Neutron stars are the ultra dense cores of massive stars that collapse and undergo a supernova explosion. This neutron star is located within the remains of a supernova — known as 1E 0102.2-7219 (E0102 for short) — in the Small Magellanic Cloud, located 200,000 light years from Earth.
E0102’s neutron star is different from most others because it has both a low magnetic field and does not have a star in orbit around it. Its remnant is also unusual because it contains high levels of oxygen like two other well-known supernova remnants, Cassiopeia A and Puppis A. These oxygen-rich supernova remnants are important for understanding how massive stars fuse lighter elements into heavier ones before they explode.