About J0555+3948
J0555+3948 is an uncommon pulsar. It spins once every 1,146.906 ms and has a dispersion measure of 36.1 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.