And because white dwarfs are among our cosmos' oldest stellar objects, with predictable life stages, astronomers often use them as "clocks" to date surrounding groups of stars. "The sun itself will become a crystal white dwarf in about 10 billion years".
Eventually white dwarfs cool down into black dwarfs when they give off no more heat.
Prior to crystallization, atoms are thought to be packed so tightly in the core of a white dwarf that their electrons become unbound, leaving a conducting electron gas and positively charged nuclei in a fluid form. The work verified earlier predictions that such a catalog of white dwarf stars would reveal a number in the slow process of turning from what is essentially a liquid form to a solid state.
Data was compiled by the European Space Agency's Gaia and analyzed over a span of five years, looking at approximately 15,000 white dwarfs within close proximity to the Sun, approximately 330 light-years away. Gaia does this by precisely monitoring the positions of huge numbers of stars; the mission team aims to study 1 billion stars over the spacecraft's operational lifetime.
The oldest white dwarfs, nearly the age of the Milky Way, are likely to be almost fully crystal Discovery published in Nature exactly fifty years after it was predicted.
Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma.
Further analysis and modeling suggested that the odd "pile-up" is due to the crystallization process. Therefore, gaining a greater understanding of how crystallization can stave off the cooling process, essentially making the stars appear younger than they really are, would help astronomers improve the accuracy of the white dwarf dating technique. "It was predicted 50 years ago that we should observe a pileup in the number of white dwarfs at certain luminosities and colors due to crystallization, and only now this has been observed".
According to the authors of the new paper, the release of heat energy alone would not be enough to account for their observations. "This will push the carbon upward, and that separation will release gravitational energy". It's not a freaky science fiction plot, but the takeaway of new scientific research published this week in the journal Nature.