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| Titel |
Retrieval of temperatures from near-IR reflectance spectra of water-ice-rich bodies: application to Saturn's satellites and rings |
| VerfasserIn |
Gianrico Filacchione, Fabrizio Capaccioni, Roger N. Clark, Phil D. Nicholson, Matt M. Hedman, Mauro Ciarniello, Emiliano D'Aversa, Robert H. Brown, Dale P. Cruikshank, Jeffrey N. Cuzzi, Bonnie J. Buratti, Linda J. Spilker, Nicolas Altobelli, Cristina M. Dalle Ore, Priscilla Cerroni |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094964
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| Publikation (Nr.) |
 EGU/EGU2014-10400.pdf |
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| Zusammenfassung |
| Crystalline water ice reflectance is characterized by a peak at about 3.6 μm that has
temperature-dependent properties (Filacchione et al., 2012). Optical constants measured in
transmittance by Mastrapa et al (2009) in the range of temperature between 20 and 150 K
show that the peak’s position changes with the temperature. The same trend is observed on
reflectance measurements realized by Clark et al. (2012) on small grains of pure water ice at
standard illumination conditions (phase=30 deg) for temperature of the sample varying
between 88 K and 172 K. The analysis of these data demonstrates that the 3.6 μm
peak shifts towards shorter wavelengths when the ice is cooled, moving from about
3.675 μm at T=172 K to about 3.58 μm at T=88 K. Starting from this experimental
evidence we have used a 4th-degree polynomial fit in the 3.2-3.8 μm range to measure
the wavelength at which the peak occurs on laboratory data with the view toward
using it as a marker to retrieve similar temperatures of the ring particles and of the
regular icy satellites of Saturn. We report about the results obtained after having
applied this method to three different datasets: a) a sample of 240 disk-integrated
observations of Saturn’s regular satellites collected by VIMS between 2004 and 2011 with
solar phase in the 20-40 deg range, corresponding to late morning-early afternoon
local times. From these observations we have retrieved average temperatures for
Mimas (88 K), Enceladus ( |
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