Astronomers say they have found a planet "55 Cancri e," twice the size of Earth, orbiting a star much like our Sun and visible to the naked eye in the constellation of Cancer. They say the planet is made largely out of diamond.
According to Yale News, a team of US and French researchers discovered the planet. National Geographic reports it was first detected in 2011, as it crossed the front of its star.
The "diamond planet" is one of five orbiting its star, 55 Cancri, located 40 light years from Earth in the constellation of Cancer, and visible to the naked eye.
Observations of the planet in orbit around its star last year, allowed astronomers to measure its radius. NASA's Spitzer Space Telescope collected data on the orbital distance of the planet. The information, with the recent estimate of its mass, allowed astronomers to determine its chemical make-up with the help of computer modelling tools, National Geographic reports.
According to Yale News, the radius of the "diamond planet" is twice the Earth's and its mass eight times. Being only twice the Earth's size and eight times its mass classifies it as a "super Earth."
The planet is composed of carbon, iron, silicon and carbide. It is very hot with temperatures on its surface as high as 3,900 degrees Fahrenheit (1,648 Celsius).
Illustration of the interior of 55 Cancri e with a surface of mostly graphite surrounding a thick layer of diamond.
Nikku Madhusudhan, Indian-born Yale researcher, who led the study, said: "The surface of this planet is likely covered in graphite and diamond rather than water and granite."
The planet orbits its star at "hyperspeed." It orbits so fast that a year on the planet is only 18 hours on Earth.
According to Madhusudhan, who carried out the study with Olivier Mousis at the Institut de Recherche en Astrophysique et Planetologie in Toulouse, France, at least a third of the mass of the planet, about three times the mass of the Earth, could be composed entirely of diamond.
This is not the first time that astronomers have discovered a "diamond planet." Bu it is the first time they have observed one orbiting a star much like our Sun. Yale News reports Madhusudhan said: "This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth." He added that discovery of the carbon-rich planet indicates it can no longer be assumed that all rocky or terrestrial planets are similar to the Earth in "chemical constituents, interiors, atmospheres or biologies."
Star map showing the planet-hosting star 55 Cancri in the constellation of Cancer
National Geographic reports Madhusudhan, remarked: "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. 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."
According to Yale News, David Spergel, a Princeton University astronomer, said: "Stars are simple -- given a star's mass and age, you know its basic structure and history. Planets are much more complex."
National Geographic reports he explained further: "Unlike our solar system, which is dominated by oxygen and silicates, this planetary system is filled with carbon. While it's still unknown exactly what implication this will have on our understanding of evolution of planetary systems, there's no doubt it is an important step towards understanding the full diversity of planets."
He added: "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."
However, astronomers have warned fortune hunters who may be mislead by their description of the new "diamond planet" as "nearby" that 55 Cancri e is about 40 light years away, or 230 trillion miles.