About J1840-0559
J1840-0559 is an uncommon pulsar. It spins once every 859.368 ms, has a dispersion measure of 319.1 pc cm⁻³ and carries a surface magnetic field around 2.91×10^12 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.