Amateur astronomer discovers fastest rotator in the Solar System
BY DR EMILY BALDWIN
ASTRONOMY NOW
Posted: May 28, 2008

A British amateur astronomer has discovered the fastest rotating asteroid in the Solar System as part of the Faulkes Telescope near-Earth asteroid project.

Astronomer Richard Miles, who is currently serving as vice- president of the British Astronomical Association, made his exciting discovery on April 29 using the Faulkes Telescope South in Australia, which he operated remotely using the Internet from his home in Dorset. Confirmation of his discovery was formally announced by the International Astronomical Union on Thursday 22 May.

Asteroid 2008HJ speeds across the sky, covering around 1,500 kilometres and almost making one complete revolution in the time it took to snap this image (top). The bottom left image shows a 15 second exposure using the 2 metre Faulkes Telescope South and the right hand image shows the same area of sky from the ESO Online Digitised Sky Survey. The white line in the left hand image shows the distance moved during the exposure. Image: Richard Miles/Faulkes Telescope South.

Asteroid 2008HJ is revolving once every 42.7 seconds, classifying it as a “superfast rotator”. The previous record holder was asteroid 2000 DO8, discovered eight years ago and found to rotate once every 78 seconds. Asteroid 2008HJ is a compact stony object some 12 metres by 24 metres in size, smaller than a tennis court yet probably having a mass in excess of 5,000 tonnes. It was moving at almost 45 kilometres per second when it hurtled past the Earth at a distance of 1 million kilometres in late April.

Example of the rotational light curve showing the asteroid's variation in brightness as it rotates, reflecting the sunlight differently as it tumbles through space. Image: Richard Miles/Faulkes Telescope South.

This latest discovery is the most recent outcome of a new Faulkes Telescope project to survey the properties of small, less than 150-metre diameter, near-Earth asteroids. UK schools and colleges have already participated in the project, which in April had an early success having found that asteroid 2008 GP3 rotates once every 11.8 minutes. The latest discovery should prove especially encouraging to schools, colleges and other amateur astronomers looking to participate in the Faulkes Telescope project, given the high chance of success. One challenge will be to find objects spinning even faster than 2008HJ!

"A discovery like this demonstrates the capabilities of amateur astronomers and school students to produce exciting scientific results if given the right tools,” says Dr Paul Roche, director of the Faulkes Telescope Project at Cardiff University. “By providing Richard with access to a big telescope we have smashed the previous record, and opened up the search for even faster objects to UK amateur astronomers and school students. This helps to put all that classroom science, maths and IT to real use!"

Our knowledge of the near-Earth population of small asteroids is very sparse, so schools and amateurs can contribute directly to our understanding of these potentially Earth-threatening objects.