Search academic texts

Information × Registration Number 0213U001492, 0110U001037 , R & D reports Title Photometric and polarimetric properties of the Moon popup.stage_title Head Shkuratov Yuriy, Registration Date 25-02-2013 Organization Kharkov National University named after V.N. Karazin popup.description2 Object of research - lunar surface and computer models of particles which forming the upper layer of lunar surface. The purpose of the research - investigation of lunar regolith structure using photometric and polarimetric data obtained by Earth-based and orbital instruments. Method of research - obtaining and analysis of the spatial distributions of phase ratios, phase dependences of color-index, and spectropolarimeric parameters for studying of photometric properties of lunar regolith; also the modeling of lightscattering by regolith particles. Our study of data AMIE onboard SMART-1 reveals photometric anomalies, from subkilometer to tens of kilometer sizes. The presented examples demonstrate the use of lunar orbital multiangular photometry to characterize the regolith microstructure; we documented geological and surface processes associated with floor-fractured craters, pyroclastic deposits, ray systems of different origin, and swirls. We present maps of the relative slope of the phase function obtained at a wavelength of 0.52 ?m and phase ratios of color-index C(600 nm/470 nm) for the near side of the Moon. The peculiarities in the phase-slope distribution found in the 2°-10° range may indicate the differences in the granulometric composition of the regolith belonging to the lava flows of different age and chemical composition. It has been found that for phase angles smaller than ? ~ 40°-50°, the color index of the highlands grows with the phase quicker than that of the mare regions. For larger phase angles, ? > 50°, a reverse situation is observed. We interpret the change in the behavior of the dependence at large phase angles, ? > 40°-60° as connected with the decrease of the multiple scattering contribution at very large phase angles. For the first time the polarimetric color ratio at a phase angle of 96° has been imaged. It has been found that spectropolarimetric observations of the Moon can give new independent information on the composition and optical properties of the lunar regolith. The images of the lunar surface areas in three polarimetric parameters, Pmin, ?inv, and h have been obtained for the first time. The difference in the behavior of these parameters and the albedo points to their potential for the remote sensing of the lunar surface. Using the method of phase ratios to assess the steepness of the phase function,we found for the first time several areas with photometric anomalies in the south-west portion of the lunar disk. The photometric anomalies can be interpreted as areas having increased surface roughness at spatial scales smaller than millimeter-decimeter. According to our theory the anomalies are regions of very fresh shallow regolith disturbances caused by impacts of meteoroid swarms consisting of rather small impactors. Using the Sh-matrix formalism we have derived analytical T-matrix solutions for both prolate and oblate spheroids, making it possible to produce analytical light-scattering calculations. Such particles are of interest as simulants in many fields including atmospheric aerosols, biological and astrophysical particles. We find that the resulting scattering patterns from these particles are strongly dependent on refractive index and size parameter. One primary advantage of using the Sh-matrix formulation is the ability for rapid calculation of a polydispersion of particles. The analytical solution presented here is especially useful for large, highly eccentric spheroids. Product Description popup.authors Зубко Є. Кайдаш В. Овчаренко А. Опанасенко М. Петров Д. Старухіна Л. Степанюк М. Шкуратов Ю. popup.nrat_date 2020-04-02 Close