About J2019+2425
J2019+2425 is an epic pulsar. It spins once every 3.935 ms, has a dispersion measure of 17.2 pc cm⁻³ and carries a surface magnetic field around 168,220,554 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.