About J1809-3547
J1809-3547 is an uncommon pulsar. It spins once every 860.388 ms, has a dispersion measure of 193.84 pc cm⁻³ and carries a surface magnetic field around 3.25×10^11 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.