About J0821-4300
J0821-4300 is an uncommon pulsar. It spins once every 112.799 ms and carries a surface magnetic field around 3.27×10^10 G.
The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.