HR: 13:40h
AN: P43B-01 [Abstracts]
TI: The Surface Composition of Saturn's Moon Phoebe
As seen by the Cassini Visual and Infrared Mapping Spectrometer
AU: * Clark, R N
EM: rclark@usgs.gov
AF: US Geological Survey, DFC, Denver, CO 80225
United States
AU: Brown, R H
EM: hb@lpl.arizona.edu
AF: U. of Arizona, LPI, Tucson, AZ 85721
United States
AU: Jaumann, R
EM: Ralf.Jaumann@dlr.de
AF: GAC, DLR, Berlin, D-12489
Germany
AU: Cruikshank, D P
EM: dcruikshank@mail.arc.nasa.gov
AF: NASA, Ames, Moffett Field, CA 94035
United States
AU: Nelson, R M
EM: robert.m.nelson@jpl.nasa.gov
AF: JPL, Caltech, Pasadena, CA 91109
United States
AU: Buratti, B J
EM: bonnie.j.buratti@jpl.nasa.gov
AF: JPL, Caltech, Pasadena, CA 91109
United States
AU: McCord, T B
EM: mccordtb@aol.com
AF: PSI, UH, Winthrop, WA 98862
United States
AU: Lunine, J
EM: jlunine@lpl.arizona.edu
AF: U. of Arizona, LPI, Tucson, AZ 85721
United States
AU: Hoefen, T
EM: thoefen@usgs.gov
AF: US Geological Survey, DFC, Denver, CO 80225
United States
AU: Curchin, J M
EM: jcurchin@usgs.gov
AF: US Geological Survey, DFC, Denver, CO 80225
United States
AU: Hansen, G
EM: ghansen@rad.ess.washington.edu
AF: U. W., annex a, Seattle, WA 98195
United States
AU: Hibbits, K
EM: hibbitts@psi.edu
AF: PSI NW, Corp Ctr, Pasadena, CA 91101
United States
AU: Matz, K
EM: matz@dlr.de
AF: GAC, DLR, Berlin, D-12489
Germany
AU: Baines, K H
EM: kbaines@pop.jpl.nasa.gov
AF: JPL, Caltech, Pasadena, CA 91109
United States
AU: Bellucci, G
EM: giancarlo.bellucci@ifsi.rm.cnr.it
AF: IFSI, CNR, Rome, 00133
Italy
AU: Bibring, J
EM: jean-pierre.bibring@ias.fr
AF: U. de Paris, Sud-Orsay, Orsay Cedex, 91405
France
AU: Bussoletti, E
EM: bussoletti@nava1.uninav.it
AF: U Navale, I Fisica, Napoli, 80133
Italy
AU: Capaccioni, F
EM: capaccio@rm.iasf.cnr.it
AF: Istituto di Astrofisica, .Spaziale, Rome, 00133
Italy
AU: Cerroni, P
EM: priscio@rm.iasf.cnr.it
AF: Istituto di Astrofisica, .Spaziale, Rome, 00133
Italy
AU: Coradini, A
EM: coradini@rm.iasf.cnr.it
AF: Istituto di Astrofisica, .Spaziale, Rome, 00133
Italy
AU: Formisano, V
EM: formisan@nike.ifsi.rm.cnr.it
AF: IFSI, CNR, Rome, 00133
Italy
AU: Filacchione, G
EM: gianrico@rm.iasf.cnr.it
AF: Istituto di Astrofisica, .Spaziale, Rome, 00133
Italy
AU: Langevin, Y
EM: yves.langevin@ias.fr
AF: Institut d'Astrophysique Spatial, Spatiale, Orsay, 91405
France
AU: Matson, D L
EM: Dennis.L.Matson@jpl.nasa.gov
AF: JPL, Caltech, Pasadena, CA 91109
United States
AU: Nicholson, P D
EM: nicholso@astrosun2.astro.cornell.edu
AF: Cornell U., Space Sci, Ithaca, NY 14853
United States
AU: Sicardy, B
EM: bruno.sicardy@obspm.fr
AF: Obs. de Paris, .Meudon, Meudon, 92195
France
AU: Sotin, C
EM: sotin@chimie.univ-nantes.fr
AF: Laboratoire de Planitologie et, .Giodynamique, Nantes, 44072
France
AB:
The Cassini-Huygens spacecraft encountered
Phoebe on June 11, 2004. The Visual and
Infrared Mapping Spectrometer (VIMS)
obtained spatially resolved hyperspectral
images of Phoebe at 352 wavelengths (0.4-5
microns) from 8:47 UT June 11, 2004 at at an
initial range of 245,833 km and phase angle
of 84.9 degrees, to 10:22 UT June 12, 2004
at a final range of 338,401 km and a phase
angle of 92.2 degrees. The closest image
was obtained on June 11 at 19:32 UT at a
range of 2,178 km and solar phase angle of
24.6 degrees. The spatial mapping of the
VIMS, with an instantaneous field of view of
0.25 by 0.5 milliradian resulted in spatial
coverage at full spectral resolution as
small as 1 km/pixel. The spatially resolved
spectra of Phoebe indicate a low surface
albedo, from <1 to ~6% reflectance with a
variety of absorption features due to
materials which occur with variable
abundances and/or grain sizes in different
locations on the body. These include:
water ice (previously identified by Owen et
al, 1999), bound water, and trapped CO2. A
broad 1-micron feature is interpreted to be
due to Fe2+ bearing minerals. Water ice is
observed with absorptions at 3.1, 2, 1.5,
1.25, and 1.04 microns. Variable absorption
strengths indicate a variety of ice
abundances ranging from almost non detect to
>50% and grain sizes less than a few hundred
microns. Absorptions located in the 3.3 and
1.7 micron region indicate the presence of
organic molecules, and a prominent
absorption at 2.42 microns is best explained
by a cyanide compound. Spectral structure
at 4.8-5 microns is also consistent with
cyanide compounds. Absorptions at 4.5, 3.3
and 1.7 microns indicate a probable nitrile
compound. These compounds argue for either
an outer solar system origin for Phoebe, or
that its surface has been coated with outer
solar system materials.
DE: 5410 Composition
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting