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Icy craters on the Galilean satellites?
Icarus, 1978The high degree of echo depolarization observed for linearly polarized incident waves in the case of radar observations of Europa, Ganymede, and Callisto is consistent with a rough, icy surface. Measurements with circularly polarized waves, however, conducted in 1976 suggest that the types of surface irregularities found on the Galilean satellites must
Steven J. Ostro, Gordon H. Pettengill
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How fast do Galilean satellites spin?
Icarus, 1984Each of the Galilean satellites, as well as most other satellites whose initial rotations have been substantialy altered by tidal dissipation, has been widely assumed to rotate synchronously with its orbital mean motion. Such rotation would require a small permanent asymmetry in the mass distribution in order to overcome the small mean tidal torque ...
Richard Greenberg +1 more
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Internal structures of the Galilean satellites
Icarus, 1981New models for the interiors of Io, Ganymede, and Callisto are proposed. The model of Io consists of a thin, high-rigidity outer layer separated from a solid interior by a thin, molten or partially molten shell. The modulus of rigidity of the outer layer must be at least 100 times larger than that of the underlying partially molten shell.
Schubert, G. +2 more
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Masses of the Galilean Satellites of Jupiter
Science, 1976Numerical data derived from the observation of the four great satellites of Jupiter are compared with the values obtained through Sampson's theory by using the new JPL (Jet Propulsion Laboratory) system of masses. It is not possible to fit the coefficient of the free oscillation in the longitude of Ganymede, whose argument is l
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Thermal properties of the Galilean satellites
Icarus, 1973Radiometry in the 20-micron band of eclipses of each of the four Galilean satellites of Jupiter provides information about the thermal properties of the uppermost surface layers of these bodies. Their thermal inertias are all smaller than those of the moon or of Mercury; there is no evidence for atmospheres, and where the data are of high quality ...
David Morrison, Dale P. Cruikshank
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VLA observations of the Galilean satellites
Icarus, 1984Io, Europa, Ganymede, and Callisto have been observed at 2 and 6 cm with the VLA, when the Jovian system was about 4.46 AU from the earth. Flux densities and corresponding disk brightness temperatures are determined for the two wavelengths. The radio brightness temperatures are lower than in the IR, with the latter generally being consistent with the ...
Imke de Pater +2 more
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Early eclipses of the Galilean satellites
Celestial Mechanics, 1982A brief summary of the development of the theory of motion of the Galilean satellites is presented. Over 7700 eclipse observations have been collected and reduced using the Ephemeris E-2. They are of great potential in improving the ephemerides of the satellites and can yield important information on the evolution of the Galilean system.
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Galilean satellite tour orbit determination assessment
25th AIAA Aerospace Sciences Meeting, 1987Results are given which demonstrate the ability of the orbit determination system to satisfy accuracy requirements in support of the Galileo Project's planned tour of Jupiter's satellites. The results are derived through the application of mission operation strategies and assumptions.
B. MOULTRIE +4 more
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Galilean satellite mutual occultation data processing
Icarus, 1975Results of processing seven mutual occultation lightcurves are presented. The lightcurves were obtained using the 60-in. telescope (152 cm) at Mt. Wilson to observe six J1 occulting J2 events and one J3 occulting J2 event. Using a uniformly illuminated disk model, local satellite Jovicentric longitude corrections of 675 plus or minus 150 km, 275 plus ...
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Galilean satellite eclipse studies I. Observations and satellite characteristics
Icarus, 1980Spectrophotometric light curves of 12 Galilean satellite eclipses are reported. The observations were made in 20 to 30 channels over the wavelength range 3240 to 10,500 A using the 200-in. telescope. The initial data processing is described. These data measure the Jovian aerosol content in the lower stratosphere and uppermost troposphere and the ...
Thomas F. Greene +2 more
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