About J1923+1706
J1923+1706 is an uncommon pulsar. It spins once every 547.209 ms, has a dispersion measure of 142.5 pc cm⁻³ and carries a surface magnetic field around 1.55×10^11 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.