Observations with the Visual and Infrared Mapping Spectrometer (VIMS) during Cassini's flyby of Jupiter (original) (raw)
NASA/ADS
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- Baines, K. H. ;
- Bellucci, G. ;
- Bibring, J. -P. ;
- Buratti, B. J. ;
- Capaccioni, F. ;
- Cerroni, P. ;
- Clark, R. N. ;
- Coradini, A. ;
- Cruikshank, D. P. ;
- Drossart, P. ;
- Formisano, V. ;
- Jaumann, R. ;
- Langevin, Y. ;
- Matson, D. L. ;
- McCord, T. B. ;
- Mennella, V. ;
- Nelson, R. M. ;
- Nicholson, P. D. ;
- Sicardy, B. ;
- Sotin, C. ;
- Amici, S. ;
- Chamberlain, M. A. ;
- Filacchione, G. ;
- Hansen, G. ;
- Hibbitts, K. ;
- Showalter, M.
Abstract
The Cassini Visual and Infrared Mapping Spectrometer (VIMS) is an imaging spectrometer covering the wavelength range 0.3-5.2 μm in 352 spectral channels, with a nominal instantaneous field of view of 0.5 mrad. The Cassini flyby of Jupiter represented a unique opportunity to accomplish two important goals: scientific observations of the jovian system and functional tests of the VIMS instrument under conditions similar to those expected to obtain during Cassini's 4-year tour of the saturnian system. Results acquired over a complete range of visual to near-infrared wavelengths from 0.3 to 5.2 μm are presented. First detections include methane fluorescence on Jupiter, a surprisingly high opposition surge on Europa, the first visual-near-IR spectra of Himalia and Jupiter's optically-thin ring system, and the first near-infrared observations of the rings over an extensive range of phase angles (0-120°). Similarities in the center-to-limb profiles of H +3 and CH 4 emissions indicate that the H +3 ionospheric density is solar-controlled outside of the auroral regions. The existence of jovian NH 3 absorption at 0.93 μm is confirmed. Himalia has a slightly reddish spectrum, an apparent absorption near 3 μm, and a geometric albedo of 0.06±0.01 at 2.2 μm (assuming an 85-km radius). If the 3-μm feature in Himalia's spectrum is eventually confirmed, it would be suggestive of the presence of water in some form, either free, bound, or incorporated in layer-lattice silicates. Finally, a mean ring-particle radius of 10 μm is found to be consistent with Mie-scattering models fit to VIMS near-infrared observations acquired over 0-120° phase angle.
Publication:
Icarus
Pub Date:
August 2003
DOI:
Bibcode: