title: Organics and other molecules in the surfaces of Callisto and Ganymede.
abstract: Five absorption features are reported at wavelengths of 3.4, 3.88, 4. 05, 4.25, and 4.57 micrometers in the surface materials of the Galilean satellites Callisto and Ganymede from analysis of reflectance spectra returned by the Galileo mission near-infrared mapping spectrometer. Candidate materials include CO2, organic materials (such as tholins containing C(triple bond)N and C-H), SO2, and compounds containing an SH-functional group; CO2, SO2, and perhaps cyanogen [(CN)2] may be present within the surface material itself as collections of a few molecules each. The spectra indicate that the primary surface constituents are water ice and hydrated minerals.
authors.affiliation: Hawaii Institute of Geophysics and Planetology, University of Hawaii, Honolulu, HI 96822, USA. tom@kahana.pgd.hawaii.edu
authors.forename: T B
authors.initials: TB
authors.lastname: McCord
authors.forename: R W
authors.initials: RW
authors.lastname: Carlson
authors.forename: W D
authors.initials: WD
authors.lastname: Smythe
authors.forename: G B
authors.initials: GB
authors.lastname: Hansen
authors.forename: R N
authors.initials: RN
authors.lastname: Clark
authors.forename: C A
authors.initials: CA
authors.lastname: Hibbitts
authors.forename: F P
authors.initials: FP
authors.lastname: Fanale
authors.forename: J C
authors.initials: JC
authors.lastname: Granahan
authors.forename: M
authors.initials: M
authors.lastname: Segura
authors.forename: D L
authors.initials: DL
authors.lastname: Matson
authors.forename: T V
authors.initials: TV
authors.lastname: Johnson
authors.forename: P D
authors.initials: PD
authors.lastname: Martin
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D006838:Hydrocarbons / Q000032:analysis; D007053:Ice; D018538:Jupiter; D009570:Nitriles / Q000032:analysis*; D013057:Spectrum Analysis; D013455:Sulfur / Q000032:analysis*; D013458:Sulfur Dioxide / Q000032:analysis; D014867:Water
chemical_list: D006838:Hydrocarbons; D007053:Ice; D009570:Nitriles; D014867:Water; D013458:Sulfur Dioxide; D002245:Carbon Dioxide; C011206:cyanogen; D013455:Sulfur