About J1909+1148
J1909+1148 is an uncommon pulsar. It spins once every 448.945 ms, has a dispersion measure of 199.8 pc cm⁻³ and carries a surface magnetic field around 1.83×10^11 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.