SIZE AND DENSITY ESTIMATION FROM IMPACT TRACK MORPHOLOGY IN SILICA AEROGEL: APPLICATION TO DUST FROM COMET 81P/WILD 2
- Department of Earth and Space Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan)
- Office for Planning and Management, The University of Aizu, Aizuwakamatsu, Fukushima 965-8580 (Japan)
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan)
- Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, Nagatsuta, Yokohama 226-8502 (Japan)
- Department of Earth and Planetary Sciences, Kobe University, Nada, Kobe 657-8501 (Japan)
- Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan)
- Geological Survey of Japan, Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8567 (Japan)
A large number of cometary dust particles were captured with low-density silica aerogel during the NASA Stardust mission. The dust particles penetrated into the aerogel and formed various track shapes. To estimate the properties of the dust particles, such as density and size, based on the morphology of the tracks, we carried out systematic experiments testing impacts into low-density aerogel at 6 km s{sup -1} using projectiles of various sizes and densities. We found that the maximum track diameter and the ratio of the track length to the maximum track diameter in aerogel are good indicators of projectile size and density, respectively. Based on these results, we estimated the size and density of individual dust particles from comet 81P/Wild 2. The average density of the 'fluffy' dust particles and the bulk density of all dust particles were obtained as 0.35 {+-} 0.07 and 0.49 {+-} 0.18 g cm{sup -3}, respectively. These statistical data provided the content of monolithic and coarse grains in the Stardust particles, {approx}30 wt%. Combining this result with some mid-infrared observational data, we found that the content of crystalline silicates is {approx}50 wt% or more of non-volatile material.
- OSTI ID:
- 22004367
- Journal Information:
- Astrophysical Journal, Vol. 744, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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