About J1634-5640
J1634-5640 is an uncommon pulsar. It spins once every 224.201 ms, has a dispersion measure of 148 pc cm⁻³ and carries a surface magnetic field around 9.70×10^10 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.