Observations of Jupiter and the Galilean Satellites at 10 Microns.

Abstract

The 200-inch Hale telescope has been used to map the 8-l4-it brightness-temperature distribut across the disk of Jupiter and to observe the integral brightness temperatures of the Galilean satelli Other than simple limb-darkening no latitudinal variation of brightness temperature greater than ab 1.00 K was observed, nor were there variations greater than about 0.50 K across the band structur the Great Red Spot. However, an enhancement of the 8-l4-it radiation of possibly as much as thirty tk was found to be associated with the position on the disk of a satellite shadow. The observed integral brightness temperatures of Ganymede, and especiaUy Callisto, exceed the li for an insulating gray body heated only by absorbed solar radiation. Thus either these satellites dep significantly from Planckian distribution of emitted radiation or there is a large systematic effect in' observations leading to overestimates of brightness temperature. If the latter were to be the case, should have to revise the 8-l4-it brightness temperature of Venus downward from the 2150 K va obtained concurrently with the observations of this paper, a correction which widens, rather than r rows, the disparity between our Venus temperature and other published values.