About J0357+3205
J0357+3205 is an uncommon pulsar. It spins once every 444.104 ms and carries a surface magnetic field around 2.43×10^12 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.