About J1928+1725
J1928+1725 is an uncommon pulsar. It spins once every 289.838 ms and has a dispersion measure of 135.96 pc cm⁻³.
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.