A white dwarf turns into a…cosmic diamond
An impressive phenomenon
Astronomers have spotted a white dwarf-type star in our own cosmic neighborhood, just 104 light-years away, that appears to be turning into a giant diamond. The white dwarf, composed mainly of carbon and metallic oxygen, began to crystallize and transform into a dense ” cosmic diamond “. The research has not yet passed peer review and has been published on arXiv .
Stars that have eight times the mass of our Sun and below, at the end of their lives and after they have burned all their fuel, they turn into white dwarfs. When the fuel runs out, the star’s outer material is lost to space, and the core, no longer supported by the outward pressure of fusion, collapses into a superdense object about the size of Earth but with a mass equal to 1.4 Suns. The matter in the white dwarf is highly compressed and cools over time. When they lose all their heat they become a cold mass of crystallized carbon.
Calculations show that such a process takes four million years, and since the universe is only 13.8 billion years old, it is impossible to find such a star. But we can detect signs of crystallization beginning in the cores of white dwarfs.
Whether the white dwarf crystal is a diamond remains unknown. The density of white dwarfs is about 1 million kilograms per cubic meter, while the density of diamond is 3,500 kilograms per cubic meter. The age of this particular white dwarf appears to be 4.2 billion years.
We suggest that the discovery of this system just 32 parsecs away indicates that similar systems containing crystallized white dwarfs are likely numerous. Future discoveries will allow more tests of white dwarf crystallization models. We conclude that the discovery of the HD 190412 system opens a new avenue for understanding crystallized white dwarfs.
