16 Oct 2012

'Diamond planet' found by research team

11:43 am on 16 October 2012

Astronomers have discovered a planet twice the size of Earth and 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 US-French research team, its radius is twice that of Earth's but it is much more dense with a mass eight times greater.

It is also incredibly hot, with temperatures on its surface reaching 2,148°C, Reuters reports.

Yale researcher Nikku Madhusudhan and Olivier Mousis at the Institut de Recherche en Astrophysique et Planetologie in Toulose, France carried out the study. The findings are due to be published in the journal Astrophysical Journal Letters.

The study 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," Mr Madhusudhan said.

Fortune hunters might be disappointed to learn 55 Cancri e is some 40 light years, or 370 trillion kilometres, from Earth.