About J1555-2341
J1555-2341 is an uncommon pulsar. It spins once every 532.578 ms, has a dispersion measure of 51.9 pc cm⁻³ and carries a surface magnetic field around 6.15×10^11 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.