About J1659-1305
J1659-1305 is an uncommon pulsar. It spins once every 640.958 ms, has a dispersion measure of 60.37 pc cm⁻³ and carries a surface magnetic field around 6.37×10^11 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.