About J1901+0511
J1901+0511 is an uncommon pulsar. It spins once every 4,600.369 ms, has a dispersion measure of 410 pc cm⁻³ and carries a surface magnetic field around 1.09×10^13 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.