About J2008+3139
J2008+3139 is an uncommon pulsar. It spins once every 226.119 ms, has a dispersion measure of 223.9 pc cm⁻³ and carries a surface magnetic field around 1.38×10^11 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.