Astronomers have found many exotic exo-planet since the first Hot Jupiter was inferred in 1995 roasting in a tight orbit around the very sun-like star 51 Pegasus. Since then speculation and some preliminary indication of water worlds, methane planets, gas dwarfs and super earths has become regular fare. Another possible composition dreamed up by planetary scientists is a carbon world, usually presented as a dismal black and sooty planet like the one below.
But carbon forms another stable structure under enough pressure and scientists have found a planet that just might fit that glittering bill:
In addition, “we are very confident it has a density about 18 times that of water,” said study leader Matthew Bailes, an astronomer at the Swinburne Centre for Astrophysics & Supercomputing in Melbourne, Australia. “This means it can’t be made of gases like hydrogen and helium like most stars but [must be made of] heavier elements like carbon and oxygen, making it most likely crystalline in nature, like a diamond.”
The weird object is 4000 light-years away and estimated five times the size of earth. The density is the real giveaway: this object is 18 times heavier than water.
Moreover, it circles a neutron star. Neutron stars are the corpse of massive stars that blew up, leaving a tiny core of degenerate matter weighing thousands to millions of tons per cubic inch often spinning wildly. It’s far from clear exactly how the world ended up orbiting such an unusual partner. One possibility is the original system was a binary and the companion a
red-dwarf star which was denuded of its gaseous envelope in the ancient super nova, leaving behind a core of carbon and oxygen (Not sure exactly how that would work, see comment by Amphiox below). Or the object could have grown out of the heavy element rich nebula formed by a large exploding star similar to the way scientists believe traditional planets form out of the material surrounding young stars.
Whatever it is, or however it came to be, I say we call it Diamondus.