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Bigger Diamonds

January 11, 2013

Cancer, the crab, scuttles high across the sky on January nights. It’s not that much to look at — a sprinkle of faint stars between Gemini and Leo. One of those stars is quite a treasure, though. It has at least five planets, making it one of the busiest planetary systems outside our own. And one of those planets may be made largely of diamond.

The planet is 55 Cancri E. It’s a good bit bigger and heavier than Earth. A recent study said that as much as a third of it may be made of diamond, with diamonds as common on the surface as granite is here on Earth.

In part, that’s because the parent star contains a lot of the raw ingredient for diamonds: carbon. Adding high heat and pressure transforms it into its crystalline form: diamond.

55 Cancri E is far from the biggest diamond out there. An object that orbits a pulsar appears to be a diamond about 35,000 miles in diameter — the core of a once-normal star that was stripped of almost all its mass by the neutron star.

And a smaller but heavier stellar core forms an even more massive diamond — one that’s about two-thirds the mass of the Sun. The core is a white dwarf — the last remnant of a once-normal star like the Sun. This small, dense stellar corpse is made of carbon and oxygen. Over a couple of billion years, its center cooled enough for the carbon to crystallize — forming the biggest diamond yet discovered.

The core of the Sun may become a diamond as well — billions of years from now.


Script by Damond Benningfield, Copyright 2012

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