Surface reflectance analysis of small bodies on different scales
by Nafiseh Masoumzadeh Jouzdani
Date of Examination:2015-04-09
Date of issue:2015-08-11
Advisor:Prof. Dr. Stefan Dreizler
Referee:Prof. Dr. Stefan Dreizler
Referee:Prof. Dr. Ulrich Christensen
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Abstract
English
The aim of this thesis is to model the surface reflectance of small bodies using spacecraft data i.e. asteroids Steins and Lutetia. The overall and local variation of brightness from the surface covers with different local geometries are controlled by the optical, structural, and physical properties of the surface material. Two photometric models are frequently utilized to model the scattering of light from planetary and small bodies surfaces, the one of Hapke and the one of Minnaert. In both approaches, the intensity is modeled in terms of viewing and illuminating angles with a number of photometric parameters. The Minnaert model is an empirical photometric function with two parameters, the Minnaert albedo and the limb-darkening coefficient, representing the light scattering behavior across the surface. The Hapke photometric function, is a semi-empirical model and is mathematically more complicated which is composed of five coupled parameters, known as Hapke parameters. This work focuses on the application of the Minnaert and Hapke modeling to find the optimum values of their photometric parameters from the surface reflectance of two asteroids Steins and Lutetia. I used OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) images acquired during Rosetta encounter on September of 2008 and July of 2010 of Steins and Lutetia, respectively.
Keywords: photometry; asteroids; Planetary Surface Reflectance; light scattering