Published October 11, 2012
The universe just got a bit richer with the discovery of an apparent diamond-rich planet orbiting a nearby star.
Dubbed
55 Cancri e, the rocky world is only twice the size of Earth but has
eight times its mass—classifying it as a "super Earth," a new study
says. First detected crossing in front of its parent star
in 2011, the close-in planet orbits its star in only 18 hours. As a
result, surface temperatures reach an uninhabitable 3,900 degrees
Fahrenheit (2,150 degrees Celsius)—which, along with carbon, make
perfect conditions for creating diamonds.
NASA's Spitzer Space Telescope
collected data on the planet's orbital distance and mass, and resulting
computer models created a picture of 55 Cancri e's chemical makeup.
"Science
fiction has dreamed of diamond planets for many years, so it's amazing
that we finally have evidence of its existence in the real universe,"
said study leader Nikku Madhusudhan, a postdoctoral researcher at Yale University.
"It's
the first time we know of such an exotic planet that we think was born
mostly of carbon—which really makes this a fundamental game-changer in
our understanding of what's possible in planetary chemistry."
At
only 40 light-years away, in the northern constellation Cancer, the
gemlike planet sits relatively near Earth. In dark skies, 55 Cancri
e's host star is clearly visible to the naked eye. (See gem pictures.)
Diamond Planet Has Odd Chemistry
The new models fit with previous studies that showed 55 Cancri e's parent star was abundant in carbon—much more so than our sun.
"If
we make the assumption that the star and its surrounding planets are
all born from the same primordial disk of material, then it makes sense
that the entire planetary system would be carbon rich," said
Madhusudhan, whose study will appear in an upcoming issue of the journal
Astrophysical Journal Letters.
Princeton
astronomer David Spergel believes the diamond-planet find probably
represents the first discovery of a whole new class of planets whose
chemistry has never been encountered. (Related: "'Diamond Planets' Hint at Dazzling Promise of Other Worlds.")
"Unlike
our solar system, which is dominated by oxygen and silicates, this
planetary system is filled with carbon," said Spergel, who was not
involved in the new study.
"While it's still unknown exactly what
implication this will have on our understanding of evolution of
planetary systems," he said, "there's no doubt it is an important step
towards understanding the full diversity of planets."
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