About J1954+3852
J1954+3852 is an uncommon pulsar. It spins once every 352.933 ms, has a dispersion measure of 65.36 pc cm⁻³ and carries a surface magnetic field around 1.54×10^12 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.