About J1748-2021E
J1748-2021E is an uncommon pulsar. It spins once every 16.264 ms, has a dispersion measure of 224.1 pc cm⁻³ and carries a surface magnetic field around 2.28×10^9 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.