In a remarkable celestial find, astronomers have made an intriguing discovery in our cosmic vicinity—a white dwarf star that is undergoing a fascinating transformation into a massive diamond.
This white dwarf, located just 104 light-years away, primarily consists of carbon and metallic oxygen, reported first by ScienceAlert.
Cosmic Diamond
Recent observations indicate that the center of the star is crystallizing into a dense and solid structure, resembling a 'cosmic diamond' composed of crystallized carbon and oxygen.
Led by Alexander Venner from the University of Southern Queensland in Australia, an international team of astronomers describes the discovery of a new quadruple system named HD 190412, which bears a resemblance to the well-known Sirius system and lies at a distance of 32 parsecs from Earth.
The newfound white dwarf, designated as HD 190412 C, is accompanied by three other main-sequence companions within the system.
This unique configuration presents a valuable opportunity to externally determine the total age of the crystallizing white dwarf.
The researchers aimed to empirically measure the cooling delay caused by the core crystallization process occurring in the white dwarf.
When stars exhaust their fuel, they undergo transformations. For the majority of stars, including our Sun, this metamorphosis leads to the formation of a white dwarf star.
As the outer material of the star disperses into space, the remaining core, no longer supported by fusion, contracts into an ultradense object roughly the size of Earth but with a mass equivalent to 1.4 Suns.
During the process of crystallization, the carbon and oxygen atoms contained within the white dwarf rearrange themselves, forming a structured crystal pattern. As a result, energy is released in the form of heat.
This dissipation of energy slows down the cooling rate of the white dwarf, leading to noticeable changes in its color and brightness. These distinct indicators offer valuable insights into the initial stages of crystallization.
Utilizing the precise stellar mapping data provided by the Gaia mission, the team employed a comprehensive analysis to identify multiple star systems.
Through their examination, they unveiled the gravitational link between the recently discovered white dwarf, HD 190412 C, and the previously known triple star system, HD 190412.
This identification not only expanded the system from a triplet to a quadruplet but also provided evidence that the white dwarf is presently undergoing the crystallization process.
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Is the White Dwarf a Diamond?
Although it remains uncertain whether the crystallized material within the white dwarf can be classified as a diamond, its high density makes it a plausible candidate.
White dwarfs have a density exceeding one million kilograms per cubic meter, while diamond has a density of approximately 3,500 kilograms per cubic meter. However, denser forms of carbon exist, and diamonds have been detected in space before.
The age of the HD 190412 system, approximately 7.3 billion years, provides crucial context for understanding the white dwarf's cooling process. The age of the white dwarf itself appears to be around 4.2 billion years, resulting in a discrepancy of 3.1 billion years.
This disparity suggests that the rate of crystallization has slowed the cooling rate of the white dwarf by approximately 1 billion years.
The findings of the team were published in arXiv.
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