About J1917+1121g
J1917+1121g is an uncommon pulsar. It spins once every 510.31 ms and has a dispersion measure of 303.5 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.