About J1757-16
J1757-16 is an uncommon pulsar. It spins once every 451.273 ms and has a dispersion measure of 132.2 pc cm⁻³.
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.