About J1515-5720
J1515-5720 is an uncommon pulsar. It spins once every 286.648 ms, has a dispersion measure of 480.6 pc cm⁻³ and carries a surface magnetic field around 1.34×10^12 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.