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The nature of Europa's dark non-ice surface material: Spatially-resolved high spectral resolution spectroscopy from the Keck telescope |
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| Authors: | John R Spencer William M Grundy Robert W Carlson Gary B Hansen |
| Institution: | a Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302, USA b Lowell Observatory, 1400 W. Mars Hill Rd., Flagstaff, AZ 86001, USA c European Southern Observatory, Casilla 19001, Santiago 19, Chile d Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA 91109, USA e Hawaii Institute of Geophysics and Planetary Science, Planetary Sciences Division, University of Hawaii, Honolulu, HI 96822, USA f Planetary Science Institute, University of Washington, Seattle, WA 98195, USA |
| Abstract: | We present new 1.45-1.75 μm spectra of Europa's dark non-ice material with a spectral resolution (λ/δλ) of 1200, obtained by using adaptive optics on the Keck telescope to spatially separate the spectrum of the non-ice material from that of the surrounding ice-rich regions. Despite the great increase in spectral resolution over the previous best spectra of the non-ice material, taken with Galileo's near-infrared mapping spectrometer (NIMS) with λ/δλ=66, no new fine-scale spectral structure is revealed. The smoothness of the spectra is inconsistent with available laboratory spectra of crystalline hydrated salts at Europa temperatures, but is more consistent with various combinations of non-crystalline hydrated salts and/or hydrated sulfuric acid, as have been matched to the lower-resolution NIMS spectra. |
| Keywords: | Satellites of Jupiter Europa Surfaces satellite Spectroscopy |
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