About J2155-3118
J2155-3118 is an uncommon pulsar. It spins once every 1,030.002 ms, has a dispersion measure of 14.85 pc cm⁻³ and carries a surface magnetic field around 1.14×10^12 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.