THE ALBEDO, EFFECTIVE TEMPERATURE, AND ENERGY-BALANCE OF URANUS, AS DETERMINED FROM VOYAGER IRIS DATA

Data from the Voyager infrared spectrometer and radiometer (IRIS) investigation are used to determine the albedo, effective temperature, and energy balance of Uranus. From broadband radiometric observations made over a range of phase angles 15° < α < 155°, an orbital mean value for the bolometric Bond albedo, A = 0.300 ± 0.049, is obtained, which yields an equilibrium temperature Teq = 58.2 ± 1.0°K. From thermal spectra obtained over latitudes from pole to pole, an effective temperature Teff = 59.1 ± 0.3°K is derived. This represents a substantial improvement over previously determined values. The energy balance of Uranus is therefore E = 1.06 ± 0.08; the one-standard-error upper limit of 1.14 is lower than previous results. © 1990.