About J1637-4450
J1637-4450 is an uncommon pulsar. It spins once every 252.87 ms, has a dispersion measure of 470.7 pc cm⁻³ and carries a surface magnetic field around 3.86×10^11 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.