About J1938+2012
J1938+2012 is an epic pulsar. It spins once every 2.634 ms, has a dispersion measure of 236.91 pc cm⁻³ and carries a surface magnetic field around 44,977,948 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.