About J1103-5403
J1103-5403 is a rare pulsar. It spins once every 3.393 ms, has a dispersion measure of 103.91 pc cm⁻³ and carries a surface magnetic field around 113,121,462 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.