About J0709-5923
J0709-5923 is an uncommon pulsar. It spins once every 485.268 ms, has a dispersion measure of 65 pc cm⁻³ and carries a surface magnetic field around 2.50×10^11 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.