About J2208+5500
J2208+5500 is an uncommon pulsar. It spins once every 933.163 ms, has a dispersion measure of 105.21 pc cm⁻³ and carries a surface magnetic field around 2.58×10^12 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.