Abstract
The shapes of interplanetary dust particles (IDPs) have been studied based on infrared astronomy observations and/or computer simulations. Using fractal dimension as a parameter of the shapes, the relationship between the shapes and the aggregation processes during the early stage of planetary accretion has been studied. We conducted X-ray computed microtomography (CT) on micrometeorites, collected from Antarctic ice and snow to perform three-dimensional (3-D) multifractal analyses and to estimate their shapes quantitatively. The X-ray CT measurements for forty-nine micrometeorites were performed at BL47XU and BL20XU in SPring-8. Using synchrotron radiation (SR) as an X-ray source, we obtained quantitative CT images with the effective spatial resolution of about 0.5 micrometers.Multifractal analyses enable us to estimate spatial distributions of physical quantities as their singularity spectrum f(a) of a measure where the singularity strength is a. We performed multifractal analyses based on structure functions on binary 3-D images of micrometeorites. We could not obtain multifractal spectrum with any physical meanings. This result suggests that the micrometeorites analyzed have no multifractal nature or their shapes have some singular points on the present multifractal analyses.
