Carats in the Milky Way – Discovery of the Diamond Planet

Aug 28, 2011 6:23 AM By Avi Krawitz

RAPAPORT... Don’t go counting your carats just yet, but the single largest diamond discovery has just been made. Where, you ask? About 4,000 light-years away, as part of the Milky Way’s plane of stars, about an eighth of the way towards the Galactic Center from the Earth.

If that sounds like something out of a far-fetched Star Trek episode, think again. Astronomers at the University of Manchester announced they have found a planet made of just that, diamonds.

The team first detected an unusual star called a pulsar - a small star about 20 kilometers in diameter that emits a beam of radio waves - and followed up to discover the gravitational pull of a small companion planet orbiting the pulsar. The pulsar in question, they explain, is a millisecond pulsar that spins at more than 10,000 times per minute.

The astronomers believe that the diamond planet is all that remains of a once massive star, most of whose matter was siphoned off towards the pulsar. Given the close proximity between the pulsar and its companion, the star would have lost its outer layers and over 99.9 percent of its original mass.

“This remnant is likely to be largely carbon and oxygen, because a star made of lighter elements like hydrogen and helium would be too big to fit the measured orbiting times,” said Dr Michael Keith (CSIRO), one of the research team members.

The density means that this material is certain to be crystalline: that is, a large part of the star may be similar to a diamond, the team explained.

Certainly, they believe the occurrence of such a phenomenon is as uncommon as a diamond, if not more.

“The rarity of millisecond pulsars with planet-mass companions means that producing such ‘exotic planets’ is the exception rather than the rule, and requires special circumstances,” said Dr Benjamin Stappers from The University of Manchester.

A gem of a discovery indeed, but one that is unlikely to excite gemologists as much as astronomers.