October 11, 2012
LONDON - Reuters
NASA handout artist's
rendition shows the planet 55 Cancri e
orbiting its sun in
the constellation of Cancer.
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
diamond. 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 U.S.-Franco research team, its radius is twice that
of Earth's but it is much more dense with a mass eight times
It is also incredibly hot, with
temperatures on its surface reaching 3,900 degrees Fahrenheit (1,648°
"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
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
"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
"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.
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