A diamond planet orbits a pulsar (pictured here in blue). (Credit: Swinburne University)

Solid diamond planet found

  • BY AAP with AG Staff |
  • August 26, 2011

A massive star has been transformed into a much smaller planet made of diamond, say experts.

AUSTRALIAN-LED SCIENTISTS have discovered a binary planet they believe is largely made of diamond. The international team, reports today in the journal Science that the planet is the only thing left from what was a huge star in our own Milky Way galaxy.

The researchers, led by Professor Matthew Bailes from Swinburne University of Technology in Melbourne, first detected an unusual star known as a pulsar using the Parkes Radio Telescope in central NSW.

They later confirmed their discovery with other powerful telescopes in Britain and the United States. 

Pulsars led to dwarf star discovery

Pulsars are rotating stars with a diameter of about 20km, which emit a beam of electromagnetic radiation. The team noticed that the arrival times of pulses from this particular pulsar, called J1719-143, were systematically modulated.

They deduced that a small companion planet must be orbiting the pulsar and causing a detectable gravitational pull. Further examination revealed that although the planet is relatively small (60,000km diameter, or five times bigger than the Earth) its mass is slightly more than that of Jupiter. The high density of the planet gave the team a clue to its origin. "The remnant 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," says the CSIRO's Dr Michael Keith, a member of the research team.

Unusual star system a mass of diamonds

The experts said it was certain the material is crystalline and that a large part of the star is similar to a diamond. "The rarity of millisecond pulsars with planet-mass companions means that producing such exotic planets is the exception rather than the rule, and requires special circumstances," Dr Benjamin Stappers from the University of Manchester says.

The bad news for anyone who wants to get their hands on the newly-discovered mass of diamond is that it's 4000 light-years from Earth in the constellation of Serpens. This is around an eight of the distance from our own Solar System to the centre of the Milky Way galaxy.

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