The researchers say their discovery supports the idea there may be carbon-rich, rocky planets whose terrains are made up of diamonds or graphite.
"You might see land masses and mountains made up of diamonds," the lead researcher Dr Nikku Madhusudhan told BBC News.
The study in Nature journal raises new questions about how planets are formed.
The work has been described as an astonishing astronomical tour de force. They have detected the thermal radiation (heat) from a planet 1,200 light years away using Nasa's Spitzer Space Telescope.
From this information they have calculated the composition of its atmosphere, according to Dr Marek Kukula of the Royal Greenwich Observatory in London.
Astronomers may have discovered diamond-rich exoplanet
Posted on Sunday, December 12 2010 @ 2:05 CET by Thomas De Maesschalck