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News briefs
Phoebe flyby: JPL has a news release today, and new images, summing up first results from the June 11th Cassini flyby of Phoebe, which is believed to have been trapped by Saturn while many of its sibling objects were relocated to the Edgeworth-Kuiper Belt by gravitational interactions in the early Solar System. From how Phoebe affected the Cassini spacecraft's trajectory and from its volume estimated from images, density is put at higher than frozen water (1.6 vs. 0.93 grams per cubic centimeter), but “much lighter than most rocks,” thus suggesting a mix of ice and rock.
“ [The evidince is that] Phoebe's surface is made of water ice, water-bearing minerals, carbon dioxide, possible clays and primitive organic chemicals in patches at different locations on the surface. We also see spectral signatures of materials we have not yet identified.
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Spectral measurements . . . confirmed the presence of water ice [and] provided evidence for hydrated minerals on Phoebe's surface, and detected carbon dioxide and solid hydrocarbons similar to those found in primitive meteorites. ”
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The University of Arizona also has a news release today about Phoebe spectral analysis.
Meteor news: Concerning this morning's Bootid meteor shower, SpaceWeather.com reports today that it was “modest.” “Observers in Canada and California report seeing six to ten slow-moving meteors per hour between 0230 UT and 1100 UT.” Marco Langbroek notes that, “Although indeed ‘modest’ in rates, the June Bootid activity of last night over the American continent was clearly above usual levels for this stream.”
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