Stellar Corpses

Magnetars are dense neutron stars—a type of stellar corpse—with magnetic fields billions of times stronger than any magnet on Earth. They release flashes of X-rays about every 10 seconds with an occasional gamma-ray burst. They weren’t classified as a distinct star type until 1998, nearly two decades after their telltale light shows were first spotted: In March 1979, nine spacecraft observed a release of radiation equaling the amount of energy the Sun lets off in a 1,000 years coming from the location of a supernova remnant called N49.