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Exogenic and endogenic albedo and color patterns on EuropaNew global and high-resolution multispectral mosaics of Europa have been produced from the Voyager imaging data. Photometric normalizations are based on multiple-image techniques that explicitly account for intrinsic albedo variations through pixel-by-pixel solutions. The exogenic color and albedo pattern on Europa is described by a second-order function of the cosine of the angular distance from the apex of orbital motion. On the basis of this second-order function and of color trends that are different on the leading and trailing hemispheres, the exogenic pattern is interpreted as being due to equilibrium between two dominant processes: (1) impact gardening and (2) magnetospheric interactions, including sulfur-ion implantation and sputtering redistribution. Removal of the model exogenic pattern in the mosaics reveals the endogenic variations, consisting of only two major units: darker (redder) and bright materials. Therefore Europa's visual spectral reflectivity is simple, having one continuous exogenic pattern and two discrete endogenic units.
Document ID
19860061863
Document Type
Reprint (Version printed in journal)
Authors
Mcewen, A. S. (USGS, Flagstaff; Arizona State University Tucson, AZ, United States)
Date Acquired
August 12, 2013
Publication Date
July 10, 1986
Publication Information
Publication: Journal of Geophysical Research
Volume: 91
ISSN: 0148-0227
Subject Category
LUNAR AND PLANETARY EXPLORATION
Distribution Limits
Public
Copyright
Other