Astronomers spot Earth-sized white dwarf star made of diamond

A team of astronomers have identified a faint white dwarf star that is sufficiently cool for its carbon to have crystalised into one huge diamond.

White dwarfs occur when stars like our Sun collapse into an extremely dense state around the size of Earth and composed mostly of carbon and oxygen, and the researchers believe that this objet may be around 11 billion years old, the same age as the Milky Way.

David Kaplan, a professor at the University of Wisconsin-Milwaukee, said:

“It’s a really remarkable object. These things should be out there, but because they are so dim they are very hard to find.”

Using the National Radio Astronomy Observatory’s (NRAO) Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA), as well as other observatories, Kaplan and his team discovered the object only because it has a companion pulsar, named PSR J2222-0137, with each star orbiting the other every 2.45 days.

Pulsars are remnants of exploded stars that give off powerful bursts of radio waves, which are more easily recorded on Earth. By observing the pulsar, the scientists were able to approximate that the pairof objects were approximately 900 light-years from Earth in the direction of the constellation Aquarius.