The astronomer, Richard Miles, made his exciting discovery on Tuesday 29th April using the Faulkes Telescope South, 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.
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. 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!".
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 neighbors 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.
