About J1646-2142
J1646-2142 is a rare pulsar. It spins once every 5.853 ms, has a dispersion measure of 29.72 pc cm⁻³ and carries a surface magnetic field around 223,511,995 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.