Forget the diamond as big as the Ritz. This one's bigger than planet Earth.
Orbiting a star that is visible to the naked eye, astronomers have
discovered a planet twice the size of our own made largely out of
The rocky planet, called '55 Cancri e', orbits a sun-like star in the
constellation of Cancer and is moving so fast that a year there lasts
a mere 18 hours.
Discovered by a US-Franco research team, its radius is twice that of
Earth's and its mass is eight times greater. It is also incredibly
hot, with temperatures on its surface reaching 3,900 degrees
Fahrenheit (2,148 Celsius).
"The surface of this planet is likely covered in graphite and diamond
rather than water and granite," said Nikku Madhusudhan, the Yale
researcher whose findings are due to be published in the journal
Astrophysical Journal Letters.
The study - with Olivier Mousis at the Institut de Recherche en
Astrophysique et Planetologie in Toulose, France - estimates that at
least a third of the planet's mass, the equivalent of about three
Earth masses, could be diamond.
Diamond planets have been spotted before but this is the first time
one has been seen orbiting a sun-like star and studied in such detail.
"This is our first glimpse of a rocky world with a fundamentally
different chemistry from Earth," Madhusudhan said, adding that the
discovery of the carbon-rich planet meant distant rocky planets could
no longer be assumed to have chemical constituents, interiors,
atmospheres, or biologies similar to Earth.
David Spergel, an astronomer at Princeton University, said it was
relatively simple to work out the basic structure and history of a
star once you know its mass and age.
"Planets are much more complex. This 'diamond-rich super-Earth' is
likely just one example of the rich sets of discoveries that await us
as we begin to explore planets around nearby stars."
"Nearby" is a relative concept in astronomy. Any fortune-hunter not
dissuaded by "The Diamond as Big as the Ritz", F Scott Fitzgerald's
jazz age morality tale of thwarted greed, will find Cancri e about 40
light years, or 230 trillion miles, from Park Avenue.