CfA Press Release Release No.: 04-07

For Immediate Release: Friday, February 13, 2004 Note to Editors: An image and animation to accompany this release is online at:http://www.cfa.harvard.edu/news/archive/pr0407image.html This Valentine's Day, Give The Woman Who Has Everything The Galaxy's LargestDiamond Cambridge, MA -- When choosing a Valentine's Day gift for a wife or girlfriend, you can't gowrong with diamonds. If you really want to impress your favorite lady thisValentine's Day, get her the galaxy's largest diamond. But you'd bettercarry a deep wallet, because this 10 billion trillion trillion carat monsterhas a cost that's literally astronomical! "You would need a jeweler's loupe the size of the Sun to grade thisdiamond!" says astronomer Travis Metcalfe (Harvard-Smithsonian Center forAstrophysics), who leads a team of researchers that discovered the giantgem. "Bill Gates and Donald Trump together couldn't begin to afford it." When asked to estimate the value of the cosmic jewel, Ronald Winston, CEO ofHarry Winston Inc., indicated that such a large diamond probably woulddepress the value of the market, stating, "Who knows? It may be aself-deflating prophecy because there is so much of it." He added, "It isdefinitely too big to wear!" The newly discovered cosmic diamond is a chunk of crystallized carbon 50light-years from the Earth in the constellation Centaurus. (A light-year isthe distance light travels in a year, or about 6 trillion miles.) It is2,500 miles across and weighs 5 million trillion trillion pounds, whichtranslates to approximately 10 billion trillion trillion carats, or a onefollowed by 34 zeros. "It's the mother of all diamonds!" says Metcalfe. "Some people refer to itas 'Lucy' in a tribute to the Beatles song 'Lucy In The Sky With Diamonds.'" The diamond star completely outclasses the largest diamond on Earth, the530-carat Star of Africa which resides in the Crown Jewels of England. TheStar of Africa was cut from the largest diamond ever found on Earth, a3,100-carat gem. The huge cosmic gem (technically known as BPM 37093) is actually acrystallized white dwarf. A white dwarf is the hot core of a star, left overafter the star uses up its nuclear fuel and dies. It is made mostly ofcarbon and is coated by a thin layer of hydrogen and helium gases. For more than four decades, astronomers have thought that the interiors ofwhite dwarfs crystallized, but obtaining direct evidence became possibleonly recently. "The hunt for the crystal core of this white dwarf has been like the searchfor the Lost Dutchman's Mine. It was thought to exist for decades, but onlynow has it been located," says co-author Michael Montgomery (University ofCambridge). The white dwarf studied by Metcalfe, Montgomery, and Antonio Kanaan (UFSCBrazil), is not only radiant but also harmonious. It rings like a giganticgong, undergoing constant pulsations. "By measuring those pulsations, we were able to study the hidden interior ofthe white dwarf, just like seismograph measurements of earthquakes allowgeologists to study the interior of the Earth. We figured out that thecarbon interior of this white dwarf has solidified to form the galaxy'slargest diamond," says Metcalfe. Our Sun will become a white dwarf when it dies 5 billion years from now.Some two billion years after that, the Sun's ember core will crystallize aswell, leaving a giant diamond in the center of our solar system. "Our Sun will become a diamond that truly is forever," says Metcalfe. A paper announcing this discovery has been submitted to The AstrophysicalJournal Letters for publication. Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center forAstrophysics is a joint collaboration between the Smithsonian AstrophysicalObservatory and the Harvard College Observatory. CfA scientists, organizedinto six research divisions, study the origin, evolution and ultimate fateof the universe. For more information, contact : David Aguilar, Director of Public Affairs

Harvard-Smithsonian Center for Astrophysics

Phone: 617-495-7462 Fax: 617-495-7468

daguilar@cfa.harvard.edu Christine Pulliam

Public Affairs Specialist

Harvard-Smithsonian Center for Astrophysics

Phone: 617-495-7463, Fax: 617-495-7016

cpulliam@cfa.harvard.edu