According to media reports, astronomers have discovered a rare white dwarf star 104 light-years away whose core is turning into a very dense “cosmic diamond,” The Independent reported.
As some stars, such as the Sun, approach the end of their lives, they become white dwarfs. A white dwarf is very hot when it forms, but because there is no source of energy, it cools and dissipates its energy, and some of these stars may gradually solidify and crystallize.
A team of astronomers from the University of Southern Queensland, the University of Victoria, the University of Warwick and the Kavli Institute for Astrophysics and Space Research has discovered one such white dwarf, which may have cooled and its nucleus could become a “cosmic diamond”. .
In a yet-to-be-peer-reviewed study published in the journal arXiv, scientists describe HD 190412 C, a white dwarf star about 104 light-years away, that consists primarily of carbon and metallic oxygen.
In a research paper published in the Monthly Notices of the Royal Astronomical Society, the scientists said: “In this work, we discovered a new quadruple system similar to the Sirius system (two companion stars orbiting the center of gravity between them. Together they form a star system, 32 parsecs away, from the previously known HD 190412 has a crystalline white dwarf companion to the triple system.
For comparison, 1 parsec is 3.26 light-years, or approximately 206.265 times the distance from Earth to the Sun.
As stars less than eight times the mass of the Sun run out of nuclear fuel and their outer stellar material loosens and is discarded, these stars often begin to collapse into white dwarfs and become denser.
If such a star is made mostly of metallic oxygen and carbon, its core becomes a giant diamond. Such stars are, of course, very faint.
Astronomers do not believe that any star has yet fully crystallized into a diamond, as mathematical calculations indicate that it would take a quadrillion years (the equivalent of a million billion). And since the universe is only about 13.8 billion years old, these stars are only at the beginning of their transitions.
With this new work, scientists believe they may have discovered a star in the early stages of this transition.
In the process, the carbon and oxygen atoms at the center of white dwarfs stop moving, form bonds, and arrange themselves into a crystalline lattice structure.
But because the crystallization process releases energy that dissipates heat, scientists say it slows down the cooling of white dwarf stars, making them appear younger than the actual age of the dead star.
Thanks to new telescopes like the European Space Agency’s GIA, it has become easier to determine a star’s distance from Earth and, accordingly, its true brightness and age.
Using data from Gaia, scientists identified the white dwarf star HD 190412 C as part of a quadruple system called HD 190412, similar to the Sirius system.
New observations of the white dwarf indicate that it is undergoing a crystallization process. Based on the study of other stars in the system, scientists can estimate the age of the white dwarf.
The science team believes that the star system is about 7.3 billion years old, and that the crystallized white dwarf may be about 4.2 billion years old.
Scientists say the discovery of this system so close to Earth indicates that there may be many similar star systems in the universe that could be useful for measuring the crystallization process.
The team wrote in the paper: “We suggest that the discovery of this system at only 32 parsecs indicates that there may be many Sirius-like systems with crystallized white dwarfs. Therefore, future discoveries may allow robust tests of crystallization models for white dwarfs.