About J0609+2130
J0609+2130 is an uncommon pulsar. It spins once every 55.698 ms, has a dispersion measure of 38.73 pc cm⁻³ and carries a surface magnetic field around 3.66×10^9 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.