About J0738+6904
J0738+6904 is an uncommon pulsar. It spins once every 6,827.693 ms, has a dispersion measure of 17.22 pc cm⁻³ and carries a surface magnetic field around 1.37×10^13 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.