About J1808-1020
J1808-1020 is an uncommon pulsar. It spins once every 596.993 ms, has a dispersion measure of 225.3 pc cm⁻³ and carries a surface magnetic field around 6.87×10^11 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.