SNAPSHOT: First Direct Evidence Stars Like Our Sun Turn Into Crystals

By Alison Mackey | January 9, 2019 3:57 pm
white dwarf stars can crystallize

One of Discover’s favorite space artists and regular contributors, Mark Garlick, created this impression of a white dwarf star solidifying to accompany the announcement. (Credit: University of Warwick/Mark Garlick)

Stars like our sun can turn into crystals in the final stages of their lives, bringing a whole new meaning to those glittering jewels in the sky. Astronomers from the University of Warwick say they’ve found the first direct evidence that white dwarf stars – the dense, stellar corpses of stars like our sun – can crystallize, or turn from a liquid into a solid. The discovery was published Wednesday in the journal Nature.

Astronomers had long suspected such crystallization was possible. But to find direct evidence, the team turned to data gathered by the European Space Agency’s Gaia satellite and analyzed some 15,000 white dwarf candidates. In the process, they uncovered a “pile-up” of stars with colors and luminosities that matched those predicted for crystallized white dwarfs.

The discovery, led by physicist Pier-Emmanuel Tremblay, was announced exactly 50 years after it was first predicted.

“All white dwarfs will crystallize at some point in their evolution,” Tremblay said in a media release. “This means that billions of white dwarfs in our galaxy have already completed the process and are essentially crystal spheres in the sky. The sun itself will become a crystal white dwarf in about 10 billion years.”

White dwarfs are extremely dense stars, so the positively charged nuclei in their cores exist as a fluid, the scientists say. But as the star cools, that fluid solidifies and creates a metal core. 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. So understanding this crystallization process could bring greater accuracy when scientists assign ages to the stars.


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CATEGORIZED UNDER: Space & Physics, top posts
  • OWilson

    I always thought a crystalline structure was less dense than a metallic one, or the more exotic denser elements in the periodic table?

    That crystals can grow and form in the extreme dense interior of a white dwarf, sounds counter-intuitive to me, but what do I know.

    Time for my daily walk, I think! :)

  • Uncle Al

    Glass is a solid. Glass is not crystalline, nor are amorphous alloys. A “crystal” presents sharp x-ray diffraction spots. Said crystal need not have translational symmetry (e.g., quasicrystals). Nomenclature is being abused.

    But as the star cools, that fluid solidifies and creates a metal core. Just what would that metal be? White dwarf cores are predominantly carbon-12 and oxygen-16, free-floating nuclei in a degenerate Fermi sea of electrons.

    • darryl

      Don’t astronomers consider any atom past helium a metal?


      • Uncle Al

        Yes, they do. Clearly the author has confused insular nomenclature with vulgate usage.


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