Callisto: Disk Temperature at 3.71 Centimeter Wavelength,

The radio emission of Callisto was studied with a three-element interferometer at the time of the 1973 opposition of Jupiter. Special care was taken to remove the residual, unresolved contribution from Jupiter itself in the antenna sidelobes. The resulting disk temperature at 3.71 centimeters, assuming a radius of 2500 plus or minus 75 kilometers for Callisto, was 101 plus or minus 25 degrees K. This is much more consistent with emission from a simple dielectric sphere than are the considerably higher temperatures that have previously been reported for wavelengths of 3.5 and 8.2 millimeters.