About J1220-6318
J1220-6318 is an uncommon pulsar. It spins once every 789.212 ms, has a dispersion measure of 347 pc cm⁻³ and carries a surface magnetic field around 2.55×10^11 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.