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MILWAUKEE — A newly discovered white dwarf star is so cold that researchers believe its carbon core has crystallized, forming a diamond in the sky.
The 11-billion-year-old white dwarf is the remnant of a star similar to the Earth’s sun, according to researchers from the University of Wisconsin- Milwaukee. They said it is likely the coldest, faintest white dwarf star astronomers have ever located.
“It’s a really remarkable object,” said assistant professor David Kaplan in a news release. “We expect a large number of old white dwarfs to be around. They are just hard to see, and if we don’t know where to look, they are basically impossible to pick out.”
The Earth-sized crystal core is the result of billions of years of cooling and fading, according to researchers. The cores of white dwarfs are made mostly of carbon and oxygen.
Astronomers were observing a nearby pulsar star when they were led to the discovery of the white dwarf star. The pulsar and its companion are gravitationally bound and orbit around each other every 2.45 days, according to the study.
Researchers believe the pulsar’s companion is a white dwarf star because of its circular orbit, according to Kaplan.
The findings were published in Astrophysical Journal on Friday.
