About J2043+7045
J2043+7045 is an uncommon pulsar. It spins once every 588 ms and has a dispersion measure of 57.64 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.