About J1001-5939
J1001-5939 is an uncommon pulsar. It spins once every 7,733.64 ms, has a dispersion measure of 113 pc cm⁻³ and carries a surface magnetic field around 2.18×10^13 G.
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.