Internal Characteristics of Phobos and Deimos from Spectral Properties and Density: Relationship to Landforms and Comparison with AsteroidsCompositional interpretations of new spectral measurements of Phobos and Deimos from Mars Express/OMEGA and MRO/CRISM and density measurements from encounters by multiple spacecraft support refined estimates of the moons' porosity and internal structure. Phobos' estimated macroporosity of 12-20% is consistent with a fractured but coherent interior; Deimos' estimated macroporosity of 23-44% is more consistent with a loosely consolidated interior. These internal differences are reflected in differences in surface morphology: Phobos exhibits a globally coherent pattern of grooves, whereas Deimos has a surface dominated instead by fragmental debris. Comparison with other asteroids .110 km in diameter shows that this correspondence between landforms and inferred internal structure is part of a pervasive pattern: asteroids interpreted to have coherent interiors exhibit pervasive, organized ridge or groove systems, whereas loosely consolidated asteroids have landforms dominated by fragmental debris and/or retain craters >1.3 body radii in diameter suggesting a porous, compressible interior.
Document ID
20130010070
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Murchie, S. L. (Johns Hopkins Univ. Laurel, MD, United States)
Fraeman, A. A. (Washington Univ. Saint Louis, MO, United States)
Arvidson, R. E. (Washington Univ. Saint Louis, MO, United States)
Rivkin, A. S. (Johns Hopkins Univ. Laurel, MD, United States)
Morris, R. V. (NASA Johnson Space Center Houston, TX, United States)