About J2339-0533
J2339-0533 is an epic pulsar. It spins once every 2.884 ms, has a dispersion measure of 8.72 pc cm⁻³ and carries a surface magnetic field around 204,081,928 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.