About J1748-2446X
J1748-2446X is an epic pulsar. It spins once every 2.999 ms and has a dispersion measure of 239.81 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.