About J2149+6329
J2149+6329 is an uncommon pulsar. It spins once every 380.14 ms, has a dispersion measure of 129.72 pc cm⁻³ and carries a surface magnetic field around 2.56×10^11 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.