title: Distribution of rock, metals, and ices in Callisto.
abstract: Radio Doppler data from a single encounter (C3) of the Galileo spacecraft with Callisto, the outermost Galilean moon of Jupiter, indicated that Callisto was probably undifferentiated. Now, similar data from a second encounter (C9) corroborate this conclusion, but more accurate data from a third encounter (C10) indicate that the rock and ice within Callisto have partially, but not completely, separated. Callisto may be differentiated into a rock-metal core less than 25 percent of Callisto's radius, an outer layer of clean ice less than 350 km thick, and a middle layer of mixed rock and ice. Models in which ice and rock are mixed all the way to the center of Callisto are also consistent with the data.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109-8099, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Anderson
authors.forename: G
authors.initials: G
authors.lastname: Schubert
authors.forename: R A
authors.initials: RA
authors.lastname: Jacobson
authors.forename: E L
authors.initials: EL
authors.lastname: Lau
authors.forename: W B
authors.initials: WB
authors.lastname: Moore
authors.forename: W L
authors.initials: WL
authors.lastname: Sjogren
mesh_terms: D005296:Ferrous Compounds; D019015:Geologic Sediments; D006112:Gravitation; D006358:Hot Temperature; D007053:Ice; D007501:Iron; D018538:Jupiter; D008670:Metals
chemical_list: D005296:Ferrous Compounds; D007053:Ice; D008670:Metals; D007501:Iron; C022597:ferrous sulfide