Infrared Spectra of the Galilean Satellites of Jupiter

Abstract

Spectra of the four Galilean satellites from 1 to 4 were obtained with a Michelson interferometer. The spectra show that the albedo of Io is quite flat and shows no absorptions in the region observed. Europa and Ganymede have large amounts of water ice on their surface. CaIlisto shows some faint ice absorptions. Upper limits of 0.5 cm-atm (STP) corresponding to 6 X 10-8 atm partial surface pressure were set for CH4 and NH3 on all four satellites. Subject headings: Jupiter - spectra, infrared