Astronomers at the University of Manchester have found an exotic planet made completely of diamond, which orbits a pulsar about 4,000 light years from Earth in the constellation Serpens.

To find the new carbon-based, astronomers from Australia, Germany, Italy, the UK and the U.S. used the Parkes 64-meter radio telescope in western New South Wales.

Scientists said that the diamond-crystal planet orbits a millisecond pulsar, named PSR J1719-1438. It is located about 4,000 light years from Earth in the constellation Serpens.

According to the study led by Professor Matthew Bailes of Swinburne University of Technology in Australia, the planet is denser than anything discovered so far, and is entirely made of carbon.

A diamond forms when carbon is put under immense pressure. Since the molecules of the planet are tightly packed together, researchers believe that it must be crystalline in nature, making it effectively a giant celestial diamond.

The evolutionary history and amazing density of the planet all suggest it is comprised of carbon -- i.e., a massive diamond orbiting a neutron star every two hours in an orbit so tight it would fit inside our own Sun, said Bailes.

The team first detected an unusual pulsating star, called a pulsar, lying some 4,000 light years away. Pulsars are tiny, dead neutron stars that are only about 12 miles in diameter and spin hundreds of times a second, emitting beam of radiation.

Irregular movements in the beams clued scientists in that there was a companion planet orbiting the pulsar, which then led them to the diamond planet.

Astronomers said only two of the 1,800 known pulsars concealed planets and it's the first diamond planet ever seen.

The scientists' measurements indicate that the planet measures up to 60,000 km across, is about five times the Earth's diameter and about 300 times heavier. It is believed to be the remnant of a once-massive star that lost its outer layers to the pulsar it orbits, leaving behind the crystallized core.

Researchers said the planet, which orbits its star every two hours and 10 minutes, is also likely to have oxygen as well as carbon. Because of its high density, scientists think that lighter elements like hydrogen and helium are not present in the planet.

The planet is likely to be largely carbon and oxygen, because a star made of lighter elements like hydrogen and helium would be too big to fit the measured orbiting times, said Michael Keith of CSIRO Astronomy and Space Science, and a member of the research study.

According to researchers, the planet has slightly more mass than Jupiter but is 20 times as dense Bailes and colleagues reported in the journal Science on Thursday. However, they are not sure enough about what the planet would look like up close.

In terms of what it would look like, I don't know I could even speculate, said Ben Stappers of the University of Manchester. I don't imagine that a picture of a very shiny object is what we're looking at here.

It's highly speculative, but if you shine a light on it, I can't see any reason why it wouldn't sparkle like a diamond, Travis Metcalfe of the National Center for Atmospheric Research told New Scientist.