About J1651-4519
J1651-4519 is an uncommon pulsar. It spins once every 517.443 ms, has a dispersion measure of 562 pc cm⁻³ and carries a surface magnetic field around 2.08×10^12 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.