A planet which really does twinkle like a diamond in the sky has been discovered by scientists – its surface is littered with the precious stones.
The planet – called 55 Cancri e – has a radius double the size of Earth’s, and weighs eight times more.
Whilst Earth’s surface is covered in water and granite, the new planet is thought to be covered in diamonds and graphite.
A new study estimates that at least a third of the planet’s mass – the equivalent of the weight of three Earths – could be diamond.
This is the first time astronomers have identified a likely diamond planet around a sun-like star and unearthed its chemical make-up.
‘This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth,’ said lead researcher Nikku Madhusudhan.
‘The surface of this planet is likely covered in graphite and diamond rather than water and granite.’
The diamond planet orbits at hyper speed – its year lasts just 18 hours, in contrast to Earth’s 365 days.
But with a blazingly hot temperature of about 3,900F, researchers say it will not live on.
It one of five planets orbiting a sun-like star, 55 Cancri, that is located 40 light years from Earth yet visible to the naked eye in the constellation of Cancer.
The planet was first observed orbiting its star last year, allowing astronomers to measure its radius for the first time.
This new information, combined with the most recent estimate of its mass, allowed Madhusudhan and colleagues to determine its chemical make-up.
Research suggests the planet has no water at all, and appears to be composed mainly of carbon (as graphite and diamond), iron, silicon carbide, and, possibly, some silicates.
‘By contrast, Earth’s interior is rich in oxygen, but extremely poor in carbon – less than a part in thousand by mass,’ says co-author and Yale geophysicist Kanani Lee.
The identification of a carbon-rich super-Earth means that distant rocky planets can no longer be assumed to have compositions similar to that of Earth.
David Spergel, professor of astronomy and chair of astrophysical sciences at Princeton University, said: ‘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.’
The paper reporting the findings has been accepted for publication in the journal Astrophysical Journal Letters.
