A white dwarf star 50 light-years away in the constellation Centaurus is actually a mind-boggling chunk of diamond two-thirds the size of the Earth, according to astronomers at the Harvard-Smithsonian Center for Astrophysics.
“You would need a jeweler’s loupe the size of the Sun to grade this diamond,” joked astronomer Travis Metcalfe, who led the team of researchers that discovered it.
Metcalfe said the weight of the galaxy’s largest diamond is 10 billion trillion trillion carats. Try that on for size!
Given the pet name “Lucy” by astronomers in deference to the Beatles’ famous song, “Lucy In The Sky With Diamonds,” the dwarf star is officially known as “BPM 37093.” It is 4,000km in diameter, and likely the coldest white dwarf ever detected.
The white dwarf star is the compressed dying remnant of what used to be a star very much like our sun. Once a star uses up its fuel, it shrinks in on itself and starts to cool off. Since it’s made mostly of carbon, the crystallization of the super-dense material produces a diamond.
Before you think about planning a mining expedition to Lucy, take note that her super-cool temperature (compared to other stars) is still a blistering 5,000°F. Our sun at its center is about 5,000 times hotter.
White dwarf stars are nearly impossible to identify because they are extremely difficult to see. Lucy, for instance, shines with only 1/2000th of the sun’s visual brightness. Lacking visual clues, astronomers have relied on other methods to pinpoint a white dwarf in space. In the case of Lucy, she happens to do an “orbital tango” with a pulsar, or fast-spinning neutron star.
Metcalf noted that in five billion years our own sun would meet the same fate as Lucy. It will cool down, shrink, crystallize and become a huge diamond in the center of our solar system.
“Our sun will become a diamond that truly is forever,” said Metcalfe.