About J2243+1518
J2243+1518 is an uncommon pulsar. It spins once every 596.799 ms, has a dispersion measure of 42.13 pc cm⁻³ and carries a surface magnetic field around 2.62×10^11 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.