The traditional picture of comets as cold, icy, unchanging bodies throughout their history is being reappraised in the light of analyses of dust grains from Comet Wild2. A team led by the University of Leicester has detected the presence of iron in a dust grain, evidence of space weathering that could explain the rusty reddish colour of Wild2’s outer surface. The results were presented by Dr John Bridges at the National Astronomy Meeting in Manchester on Tuesday 27th March.
“This is the first mineralogical evidence for space weathering that has been identified in the Wild2 samples that was hinted at by other spectroscopic observations of the comet,” said Bridges. “It adds another piece of the puzzle to our understanding of the life history of comets.”
Image above: A cometary track in aerogel analysed at Diamond, 2mm across
Image on home page: Composite image of Comet Wild 2, Courtesy NASA
See images of the Stardust mission and aerogel on the Nasa website
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