White dwarf star near Earth is crystallising into a 'cosmic diamond'

Something very similar to a glittering diamond the size of a planet and not too far from Earth has been spotted by astronomers.

A white dwarf star, it is just 104 light years away and scientists believe it is turning into a huge 'diamond' made of crystallised carbon and metallic oxygen.

White dwarf stars are the core of dead stars – and when some of them cool, they crystallise into something that might be an enormous diamond as big as the moon or even Earth.

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The research is available on preprint website ArXiv.

The diamond white dwarf was found in what had been thought to be a system of three stars, HD 190412, the scientists said.

The 'crystal' inside the white dwarf could be diamond, the astronomers believe, or it could be a denser version of carbon. The density of white dwarfs is around one million kilos per cubic metre, ScienceAlert reports.

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The researchers write: "The observational signature of core crystallisation of white dwarfs has recently been discovered.

"In this work we report that a recently discovered white dwarf is a bound companion to the triple star HD 190412, forming a new Sirius-like system in the solar neighbourhood.

"The location of HD 190412 C on the Teff−mass diagram implies it is undergoing crystallisation, making this the first confirmed crystallising white dwarf whose total age can be externally constrained."

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