タイトル（掲載誌）宇宙航空研究開発機構特別資料 = JAXA Special Publication: The Second Open Competition for the Hayabusa Asteroidal Sample Preliminary Examination Team (HASPET)
一般注記Densities of Hayabusa analog samples were measured without contamination using synchrotron X-ray microtomography at BL20XU of SPring-8 and an ultra-microbalance. The density of sample 2-1A is 6.37 +/- 0.02 g/cc. The density of sample 2-1B were scattered (5.05-7.18 g/cc). This may caused by volume estimation problem in the microtomography due to the presence of a large amount of highly absorbed materials (probably Fe-Ni metal) and less absorbed materials (probably silicates). Increment of the number of projection in the tomographic imaging will solve the problem. Three-dimensional grain size distribution of sample 2-1A was obtained by identification of individual grains in the 3-D CT (Computer-aided Tomography) images. This will give the basic physical properties of regolith, which may be present on Itokawa's surface. Several phases were recognized in the 3-D CT images using CT value histograms of the images, and their 3-D distribution maps were obtained with the spatial resolution of down to about 0.5 micrometer. This will helpful for planning later destructive analyses. The density, phase estimation (probably plagioclase, Fe-Mg silicates, troilite, kamacite and taenite in sample 2-1A and Fe-Mg silicates, kamacite and taenite in sample 2-1B if meteorites are assumed) and their modes and textures suggest possibility of an ordinary chondrite (LL (Low iron, Low metal) is favorable) with high petrologic type for sample 2-1A and a stony iron for sample 2-1B although the conclusion cannot be made definitely from the CT images alone. Subtraction microradiography was also applied to sample 2-1A to search Zr-bearing minerals effectively for the Pb-Pb dating. Any Zr-bearing minerals were not observed within the spatial resolution of about a few micrometer, but zircon grains added in sample 2-1A were easily recognized by this method.
資料番号: AA0063920004
レポート番号: JAXA-SP-05-021E
連携機関・データベース国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）
提供元機関・データベース宇宙航空研究開発機構 : 宇宙航空研究開発機構リポジトリ