About J1630+3734
J1630+3734 is an epic pulsar. It spins once every 3.318 ms, has a dispersion measure of 14.18 pc cm⁻³ and carries a surface magnetic field around 190,581,410 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.