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Detailed Reference Information |
Mills, F.P. and Brown, M.E. (2000). Thermal infrared spectroscopy of Europa and Callisto. Journal of Geophysical Research 105. doi: 10.1029/1999JE001163. issn: 0148-0227. |
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The trailing hemispheres of Europa and Callisto were observed at 9--13 μm, and a spectrum of Europa with better spectral resolution and a better signal-to-noise ratio than was previously possible has been derived. The ratio spectrum of the two satellites has a signal-to-noise ratio of approximately 30 for a spectral resolving power of approximately 50. The disk-integrated, effective color temperature ratio for the two satellites is consistent with broadband, thermal infrared photometry from previous ground-based studies and from the Galileo photopolarimeter radiometer. The ratio spectrum was combined with the average Voyager 1 spectrum of Callisto to obtain a 9--13 μm spectrum of Europa with a signal-to-noise ratio that is a factor of 10 better than that in the average Voyager spectrum of Europa. After convolving the measured spectrum to the expected width of water ice emissivity features, ~1 μm, no spectral features that could be attributed to water ice on the surface of Europa are apparent at the 0.6--0.7% level. The absence of spectral features attributable to water ice is consistent with the proposal that the equatorial region of Europa that was observed may be composed primarily of a heavily hydrated mineral. The absence of water ice features may also be the result of a large fractional abundance of fine particles, such as that found on the surface of the Moon. ¿ 2000 American Geophysical Union |
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Abstract |
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Keywords
Planetology, Solid Surface Planets, Remote sensing, Planetology, Solid Surface Planets, Surface materials and properties, Planetology, Comets and Small Bodies, Radiation and spectra, Planetology, Solar System Objects, Jovian satellites |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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