Near-Earth Asteroid 2000 PH5 Observed by School Student at Armagh Observatory

Animation made from Faulkes Telescope images.

Apostolos Christou and David Asher at the Armagh Observatory together with summer student Sharon McClure (Glenlola Collegiate, Bangor, Co. Down) have observed and imaged the unusual near-Earth asteroid 2000 PH5 during its close approach to the Earth around 27 July 2004. The observations were carried out remotely using the new 2m aperture Faulkes telescope situated on the 10,000-foot summit of Haleakala, on the island of Maui in Hawaii. They formed part of Sharon McClure's summer work experience project, supported by the Nuffield Science Bursary Scheme, which is run by the Sentinus programme in the University of Ulster at Jordanstown. The aim of the project was to image the asteroid using the Faulkes telescope, and determine its changing brightness and position in space as the small object passed near the Earth on its orbit about the Sun.

The asteroid 2000 PH5 was discovered four years ago, on 3 August 2000, by the MIT Lincoln Laboratory near-Earth Asteroid Research (LINEAR) project at the White Sands Missile Range in Socorro, New Mexico, USA. Owing to recent improvements in its known orbit, it has now received the formal numerical designation "(54509)". It is one of nearly 100,000 asteroids with reasonably well-determined orbits, many of which have been discovered by the US-based LINEAR programme within the past few years. On the 27 July 2004, owing to its close proximity to the Earth at that time, just 6 times the distance to the Moon or approximately 2,300,000 km, the asteroid appeared to race across the sky, covering a distance equal to the apparent diameter of the Moon every hour.

The images captured during the one-hour session with the Faulkes telescope will be examined for changes in brightness as the small, probably elongated, 150m size object tumbles through space on its orbit. The asteroid has one of the shortest known rotation periods for such a body, just 12 minutes, suggesting that it is likely to be a piece of rock or metal, rather than the expected loose aggregate of boulders known as a 'rubble pile'.

As well as its shape, the asteroid has an unusual orbit with a period of revolution about the Sun almost exactly the same as that of the Earth. This means that, as seen from the Earth, it appears to move in a kind of horse-shoe shaped orbit about the Sun, with the Earth at the opening of the horse-shoe. For the next two years the asteroid will return annually to the Earth's vicinity, but over longer time-scales it will gradually move away from the Earth owing to its orbital period being slightly less than that of the Earth.

With an orbit in the same plane as that of the Earth and having the same mean distance from the Sun the asteroid is particularly accessible by spacecraft, and it may one day become the target of a crewed mission to a near-Earth object. More information on the asteroid's physical properties and motion can by found at www.gps.caltech.edu/~margot/NEAs/2000PH5.

The Faulkes Telescope Project is a unique educational facility that will eventually consist of two research quality 2m telescopes, one in Hawaii and the other to be constructed in Australia. School pupils will be able to select their celestial targets and operate the telescopes themselves during normal school hours, and carry out their own research projects. The Armagh Observatory has accessed the Faulkes Telescope in Hawaii with the assistance of Robert Hill of the Armagh Planetarium and through the Planetarium's role as a regional centre for the Faulkes Telescope Project in Northern Ireland. To find out more about the Faulkes Telescope Project, visit the web site.

FOR FURTHER INFORMATION CONTACT: Apostolos Christou or John McFarland at Armagh Observatory, College Hill, Armagh, BT61 9DG; Tel: 028-3752-2928, FAX: 028-3752-7174; e-mail: aacarm.ac.uk, and jmfarm.ac.uk

Last Revised: 2004 August 2nd WWW contact:webmaster@arm.ac.uk

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