About J0415+6954
J0415+6954 is an uncommon pulsar. It spins once every 390.715 ms, has a dispersion measure of 27.45 pc cm⁻³ and carries a surface magnetic field around 1.75×10^11 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.