想要鉆石？你可以去珠寶店，也可以把碳埋在地底下等上幾十億年，你還可以搭載星際飛船，到距離地球4000光年的“死亡之星”脈沖星J1719- 1438上去。

Say you need a diamond. You could go down to the jeweler, or you could put some carbon deep underground and let it sit for a couple billion years. Or you could hop in a starship and cruise 4,000 light years over to a dead star called pulsar J1719-1438.

The pulsar is exotic on its own—it's a super-dense remnant of a star spinning at about 10,000 rpm. But far more curious is the world orbiting it, which might be called a planet if it weren't so strange.

It's about as massive as Jupiter, but much more compact. It may be the remains of a carbon-rich white dwarf star. But it's been mostly cannibalized by its pulsar companion, and is now just a shadow of its former self.

The object’s incredible density makes it subject to great internal pressure. And that pressure, acting on the carbon-rich makeup of the white dwarf, may have crystallized much of it to the particular form of carbon we call diamond. That's according to new research in the journal Science. [Citation to come.]

The next step for astronomers is to find out if the diamond planet has rings.

—John Matson