NASA: Serpens Constellation - The diamond as big as a planet

Could the Serpens constellation, 848 light years away, be home to the biggest diamond ever detected? 

(Image: NASA/JPL-Caltech/L. Cieza (University of Texas at Austin)

Cruising through the Milky Way in your reconnaissance craft, your sensors pick up a powerful radio beacon. 

Altering your course to take a closer look, you find not a ship in distress, but an ultradense sphere of neutrons, packing a sun's worth of mass into something the size of a city.

This dead remnant of a star glows red like a hot ember, and is spinning 173 times per second, emitting powerful radio beams that sweep across the sky as it rotates. While such pulsars are striking, they are nothing out of the ordinary, so you are about to resume your original course when your eye catches something sparkling near the dim red glow.

A closer look reveals it to be an orb with the mass of Jupiter and about half as wide. Sensors indicate it's made of – wait, this can't be right – diamond! Your instruments don't lie. You've just stumbled upon a 10³¹-carat diamond.