About J1930+1852
J1930+1852 is an uncommon pulsar. It spins once every 136.855 ms, has a dispersion measure of 307.3 pc cm⁻³ and carries a surface magnetic field around 1.03×10^13 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.