About J2022+2854
J2022+2854 is an uncommon pulsar. It spins once every 343.402 ms, has a dispersion measure of 24.63 pc cm⁻³ and carries a surface magnetic field around 8.16×10^11 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.