It can dwarf even the most bling of rings on Earth.
Researchers have discovered a star the size of our planet made entirely from diamond.
The coldest, faintest white dwarf star ever detected, it is so cool that its carbon has crystallized, forming the Earth-size diamond in space.
‘It’s a really remarkable object,’ said David Kaplan, a professor at the University of Wisconsin-Milwaukee.
‘These things should be out there, but because they are so dim they are very hard to find.’
Kaplan and his colleagues found this stellar gem using the National Radio Astronomy Observatory’s (NRAO) Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA), as well as other observatories.
White dwarfs are the extremely dense end-states of stars like our Sun that have collapsed to form an object approximately the size of the Earth.
Composed mostly of carbon and oxygen, white dwarfs slowly cool and fade over billions of years.
The object in this new study is likely the same age as the Milky Way, approximately 11 billion years old.
Pulsars are rapidly spinning neutron stars, the superdense remains of massive stars that have exploded as supernovas.
As neutron stars spin, lighthouse-like beams of radio waves, streaming from the poles of its powerful magnetic field, sweep through space.
When one of these beams sweeps across the Earth, radio telescopes can capture the pulse of radio waves.
The pulsar companion to this white dwarf, dubbed PSR J2222-0137, was the first object in this system to be detected.
It was found using the GBT by Jason Boyles, then a graduate student at West Virginia University in Morgantown.
The pulsar was then observed over a two-year period with the VLBA by Adam Deller, an astronomer at the Netherlands Institute for Radio Astronomy (ASTRON).
These observations pinpointed its location and distance from the Earth — approximately 900 light-years away in the direction of the constellation Aquarius.
The researchers calculated that the white dwarf would be no more than a comparatively cool 3,000 degrees Kelvin (2,700 degrees Celsius).
Our Sun at its center is about 5,000 times hotter.
Astronomers believe that such a cool, collapsed star would be largely crystallized carbon, not unlike a diamond.
Other such stars have been identified and they are theoretically not that rare, but with a low intrinsic brightness, they can be deucedly difficult to detect.
Its fortuitous location in a binary system with a neutron star enabled the team to identify this one.