Astronomers Discover Earth-Sized Diamond 112
ygslash (893445) writes Astronomers at the National Radio Astronomy Observatory announced that they have discovered what appears to be the coolest white dwarf ever detected. The white dwarf is formerly a star similar to our own sun which, after expending all of its fuel, has cooled to less than a chilly 3000 degrees Kelvin and contracted to a size approximately the same as Earth. A white dwarf is composed mostly of carbon and oxygen, and the astronomers believe that at that temperature it would be mostly crystallized, forming something like a huge diamond.
Just don't tell De Beers (Score:5, Informative)
Kelvin (Score:0, Informative)
not "degrees Kelvin"
Re:DIAMONDS DO NOT WORK THAT WAY (Score:5, Informative)
This class of white dwarf stars are a mixture of primarily oxygen and carbon. Depending on the mass the amount of carbon and oxygen are roughly the same, but sometimes there is more oxygen. As the star cools it goes through a phase transition where the core becomes crystallized. This releases heat through two mechanisms: heat of crystallization and the release of gravothermal energy.
The inner crystallized section is enhanced in oxygen. The outer fluid mantel is enriched in carbon. Calling this a diamond is simply wrong. Perhaps at some point in the distant future one of these will cool and part of it will become a form of crystal carbon, but considering that the cooling time without mantle carbon crystallization is on the order of 10 Gigayears, it is not likely this has happened yet considering that the universe is around 13.6 gigayears old.
http://iopscience.iop.org/0004-637X/486/1/413/fulltext/34903.text.html [iop.org]
The Cooling of CO White Dwarfs: Influence of the Internal Chemical Distribution