科研之友
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摘要
In situ probing of a very few cometary comae has shown that dust particles present a low albedo and it low density, and that they consist of both rocky material and refractory organics. Remote observations of solar light scattered by cometary dust provide information on the properties of dust particles in the coma of a larger set of cornets. The observations of the linear polarization in the coma indicate that the dust particles are irregular, with a size greater (on the average) than about 1 mu m. Besides, they suggest, through numerical and experimental simulations, that both compact grains and fluffy aggregates (with a power law of the size distribution in the -2.6 to -3 range), and both rather transparent silicates and absorbing organics Eire present in the coma. Recent analysis of the cometary dust samples collected by the Stardust mission provide it unique ground truth and confirm, for cornet 81 P/Wild 2, the results from remote sensing observations. Future space missions to comets should, in the next decade, lead to a more precise characterization of the structure and composition of cometary dust particles.
- 出版日期2008-11
