About J1857+0057
J1857+0057 is an uncommon pulsar. It spins once every 356.929 ms, has a dispersion measure of 82.39 pc cm⁻³ and carries a surface magnetic field around 1.41×10^11 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.