About J1717+4308A
J1717+4308A is an epic pulsar. It spins once every 3.16 ms, has a dispersion measure of 35.45 pc cm⁻³ and carries a surface magnetic field around 444,738,897 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.