A British amateur astronomer has discovered the fastest rotating natural object known in our Solar System. His observations, made using a telescope normally shared by school students and professional scientists, have proved that the newly-discovered asteroid, 2008 HJ is revolving once every 42.7 seconds, classifying it is as a 'superfast rotator'.

His discovery will boost our sparse knowledge of near Earth asteroids and is another successful find for the Faulkes Telescope near-Earth asteroid project.

The astronomer Richard Miles made his exciting discovery on Tuesday 29th April using the Faulkes Telescope South (located at Siding Spring, Australia), which he operated remotely via the Internet from his home in Dorset.

Confirmation of his discovery was formally announced by the International Astronomical Union on Thursday 22nd May. The previous record holder was asteroid 2000 DO8, discovered eight years ago and found to rotate once every 78 seconds.

The Science and Technology Facilities Council (STFC) was involved in the initial set-up of the Faulkes Telescope Project and continues to provide support.

This latest discovery is the most recent outcome of a new project to use the Faulkes Telescopes, situated in Hawaii and Australia, to survey the properties of small (<150-metre) 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. Asteroid 2008 HJ was only the fourth object observed as part of this study.

The observations suggest that 2008 HJ is a compact stony object some 12m x 24m 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 (more than 100,000 mph) when it hurtled past the Earth in late April. Despite being classified as a "near-Earth asteroid", it came no closer than 1 million km and never posed a threat to our planet.

Dr Paul Roche, the director of the Faulkes Telescope Project at Cardiff University, said: "A discovery like this demonstrates the capabilities of amateur astronomers and school students to produce exciting scientific results if given the right tools. 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!"

The early success for the Faulkes Telescope near-Earth asteroid project bodes well for the future and should prove especially encouraging to schools, colleges and other amateur astronomers looking to participate. It now appears that the chances of success are high and one challenge will be to find objects spinning even faster than 2008 HJ. Cooperation between all the observing groups, whether they are astronomers or schools students, will be essential if asteroid rotation rates are to be accurately identified.

Dr Petr Pravec, an astronomer at the Ondrejov Observatory (Czech Republic) and an expert in this field, commented: "A period of 42.7 seconds for an asteroid with a size of about 20 meters is perfectly consistent with theory ... there may be a significant population of asteroids measuring up to a few tens of metres across, rotating in less than a minute, that have not been observed until now".

Our knowledge of the near-Earth population of small asteroids is very sparse, so schools and others can contribute directly to our understanding of these nearest neighbours of ours. It is believed that most of these objects are probably fragments ejected from collisions between larger bodies which took place some time in the distant past. However, other objects may have originated when the solar nebula was formed over 4.6 billion years ago.

NOTES:

Richard Miles Biography: Richard Miles is 56 years old, retired and lives in Dorset where he has a small observatory. He is married with two children. He has been an amateur astronomer for many years having constructed his first telescope whilst still a young teenager. He joined the British Astronomical Association (BAA) in 1966. He served as President of the BAA from 2005-2007, and is currently a vice-president of the association. His professional qualifications are as a research scientist specializing in physical chemistry. He obtained his doctorate from the University of Bristol and for much of his career worked in petrochemical research and development.

Affiliation: Asteroids and Remote Planets Section British Astronomical Association Burlington House, Piccadilly, London W1J 0DU.

Additional background material:

" The Faulkes Telescope Project

The Faulkes Telescope Project is an educational charity based at the School of Physics and Astronomy at Cardiff University. Founded by UK philanthropist, Dr. Martin "Dill" Faulkes", in 2000, the project offers free access to research-grade telescopes at professional observatories in Hawaii and Australia. It is now the educational partner of the California-based Las Cumbres Observatory Global Telescope Network (LCOGTN), which is building a system of telescopes designed for research and education.

LCOGTN was founded by Wayne Rosing, the former Senior Vice-President of Engineering at Google, and is based in Santa Barbara, California. Rosing, a keen amateur astronomer since childhood, is designing and building a global network of telescopes that will be used by both researchers and educational groups.

FT South has a mirror diameter of 2-metres, stands around 8m tall and weighs almost 25 tonnes. It is a research-grade instrument, but is used by UK schools for around 4 hours each (Australian) night (corresponding with UK day time). Students can control the telescope live using a website.

+ Asteroid 2008 HJ and the latest observations

Asteroid 2008 HJ was discovered on April 25 by the LINEAR robotic survey telescope located at the Lincoln Laboratory site in Socorro, New Mexico.

It was one of two potential targets posted by the Faulkes Telescope team on their website. The asteroid was only visible for a few days as it came to within 2.8 lunar-distances of the Earth. Observations on April 28 were dogged by cloud but the next night was clear and Richard Miles of the British Astronomical Association secured the necessary observations just a few hours before closest approach.

Since the asteroid was travelling at a speed of about 45 km/sec relative to the Earth, the telescope had to be continually repositioned so as to keep it in view as it tracked across the sky. Short exposures of a few seconds yielded trailed images and a tell-tale sign of a superfast rotator was the observed change in brightness along the trail caused by the oblong-shaped asteroid turning and reflecting sunlight differently.

The analysis of the images obtained was quite a challenge as the very rapid rotation was unexpected. A period search confirmed it to be a superfast rotator, having a rotation period of just 42.67 (+/- 0.04) seconds, making it the shortest known rotation period of any natural object in our Solar System.

The data obtained by the telescope is analysed to search for a period (the time over which the asteroid rotates end-over-end, resulting in a repeating pattern of light reflections off the rocky surface), and the results for 2008 HJ show that the brightness of the object shows a clear period of 42.67 seconds.