Optical Properties of Asteroid Surface Alteration

麦克法登博士的研究将分为两个阶段：(1)实验室分析实验，模拟太阳风对小行星表面的影响，以及这些变化对光谱反射率和其他光学特性的影响。(2)将实验室结果与遥感数据在光谱反射率、偏振和光度散射特性方面进行比较。这将定义这些参数中的哪些是太阳风轰击的诊断，并定义小行星表面条件，其特定的光谱特征可归因于表面变化的影响。由于研究人员无法将遥感测量结果与某些陨石样本和陆地物质合成混合物进行令人满意的比较，因此对小行星的化学和物理状态及其演化历史的了解受到了阻碍。麦克法登博士的研究将检验太阳风轰击对陨石样本和矿物混合物的反射率和其他光学特性的影响。这将提高对小行星及其可能的陨石类似物之间关系的理解，并测试目前在解释小行星光谱反射率方面的主要假设：小行星表面由未改变的陨石物质适当地表示。

Dr. McFadden's research will have two phases: (1) Laboratory analytical experiments simulating the effects of solar wind on asteroid surfaces and the way these changes affect spectral reflectance and other optical properties. (2) Comparison of the laboratory results with remote sensing data made with respect to spectral reflectance and polarimetric and photometric scattering properties. This will define which of these parameters are diagnostic of solar wind bombardment and also define asteroid surface conditions whose specific spectral signatures are attributable to the effects of surface alteration. Understanding the chemical and physical states of asteroids and their evolutionary history has been impeded by investigators' inability to satisfactorily compare remote sensing measurements with certain samples of meteorites and synthetic mixtures of terrestrial materials. Dr. McFadden's study will examine the effects of solar wind bombardment on the reflectance and other optical properties of meteorite samples and mineral mixtures. This will improve the understanding of the relationship between asteroids and their possible meteoritic analogues, and test the current primary assumption in interpretation of asteroid spectral reflectance: that the surfaces of asteroids are represented appropriately by unaltered meteoritic materials.