18 October 2010
|Caption: Malcolm Hartley checking a photographic plate from the AAO's UK Schmidt Telescope. Image credit: Jonathan Pogson|
When NASA’s EPOXI spacecraft flies past Comet Hartley 2 on 4 November (US time), the comet’s Aussie discoverer, Malcolm Hartley, will be watching from ‘mission control’ at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Mr Hartley works for the Australian Astronomical Observatory, operating its UK Schmidt Telescope at Siding Spring Observatory near Coonabarabran in New South Wales.
It was using that telescope in 1986 that he discovered Hartley 2.
“Part of my job was to scan the Schmidt’s photographic plates by eye, and over the years I have spotted a number of comets,” Mr Hartley said.
He has 10 comets to his name. Hartley 2, his second, has a diameter of between 1.2 and 1.6 kilometres, and orbits the Sun every 6.46 years.
Mr Hartley’s trip has been arranged and funded by NASA. He departed for the USA on Wednesday 20 October.
EPOXI is the same spacecraft that in 2005 launched a projectile into comet Tempel 1, gouging out a crater and kicking up a bright dust cloud. This cloud was observed and analysed to learn about that comet’s composition, in a project called Deep Impact.
The acronym EPOXI sums up the spacecraft’s two current projects: the Deep Impact Extended Investigation (DIXI), and the Extrasolar Planet Observation and Characterization (EPOCh). The spacecraft will carry out Extrasolar Planet Observation and Characterization while cruising to Hartley 2, and the Deep Impact Extended Investigation as it flies by.
The fly-by will take EPOXI within 700 km of Hartley 2, to look for frozen compounds on the comet’s surface and map outbursts of gas, the distribution of craters, and temperature variations across the comet’s surface.
Comets formed in the outer Solar System, about 4600 million years ago, at the time the planets were forming Learning about the material in comets helps us understand the early history of the Solar System.
About 4000 comets are known, but there are estimated to be about a trillion comet-like bodies lurking in the outer Solar System.
The Australian Astronomical Observatory is part of the Commonwealth Department of Innovation, Industry, Science and Research.
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