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Distribution and properties of fragments and debris from the split Comet 73P/Schwassmann-Wachmann 3 as revealed by Spitzer Space Telescope
Reach, William T.; Lisse, Carey M.; Sykes, Mark V. +2 more
During 2006 March-2007 January, we used the IRAC and MIPS instruments on the Spitzer Space Telescope to study the infrared emission from the ensemble of fragments, meteoroids, and dust tails in the more than 3° wide 73P/Schwassmann-Wachmann 3 debris field. We also investigated contemporaneous ground-based and HST observations. In 2006 May, 55 frag…
Features around embedded moonlets in Saturn's rings: The role of self-gravity and particle size distributions
Lewis, Mark C.; Stewart, Glen R.
This paper presents the results of N-body simulations of moonlets embedded in broad rings, focusing specifically on the saturnian A ring. This work adds to previous efforts by including particle self-gravity and particle size distributions. The discussion here focuses primarily on the features that form in the background particles as a result of t…
Evidence for Mg-rich carbonates on Mars from a 3.9 µm absorption feature
Palomba, Ernesto; Zinzi, Angelo; Cloutis, Edward A. +3 more
The origin and nature of the early atmosphere of Mars is still debated. The discovery of sulfate deposits on the surface, coupled with the evidence that there are not large abundances of carbonates detectable on Mars in the optically accessible part of the regolith, leaves open different paleoclimatic evolutionary pathways. Even if carbonates are …
Geological evolution of Ares Vallis on Mars: Formation by multiple events of catastrophic flooding, glacial and periglacial processes
Komatsu, Goro; Pondrelli, Monica; Pacifici, Andrea
Ares Vallis is one of the greatest outflow channels of Mars. Using high-resolution images of recent missions to Mars (MGS, 2001 Odyssey, and Mars Express), we investigated Ares Vallis and its valley arms, taking advantage of 3-dimensional analysis performed using the high-resolution stereo capability of the Mars Express High Resolution Stereo Came…
Characteristics of Saturn's polar atmosphere and auroral electrons derived from HST/STIS, FUSE and Cassini/UVIS spectra
Feldman, P. D.; Gérard, J. -C.; Grodent, D. +3 more
Ultraviolet (UV) spectra of Saturn's aurora obtained with the Hubble Space Telescope Imaging Spectrograph (STIS), the Cassini Ultraviolet Imaging Spectrograph (UVIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have been analyzed. Comparisons between the observed spectra and synthetic models of electron-excited H 2 have been us…
Three tenuous rings/arcs for three tiny moons
Hedman, M. M.; Burns, J. A.; Cooper, N. J. +4 more
Using Cassini images, we examine the faint material along the orbits of Methone, Anthe and Pallene, three small moons that reside between the orbits of Mimas and Enceladus. A continuous ring of material covers the orbit of Pallene; it is visible at extremely high phase angles and appears to be localized vertically to within ±25 km of Pallene's inc…
Uranus at equinox: Cloud morphology and dynamics
Sromovsky, L. A.; Fry, P. M.; Showalter, M. R. +5 more
As the 7 December 2007 equinox of Uranus approached, collaboration between ring and atmosphere observers in the summer and fall of 2007 produced a substantial collection of ground-based observations using the 10-m Keck telescope with adaptive optics and space-based observations with the Hubble Space Telescope. Both near-infrared and visible-wavele…
Ion composition and chemistry in the coma of Comet 1P/Halley—A comparison between Giotto's Ion Mass Spectrometer and our ion-chemical network
Hansen, Kenneth C.; Gombosi, Tamas I.; Combi, Michael R. +3 more
In order to understand the cometary plasma environment it is important to track the closely linked chemical reactions that dominate ion evolution. We used a coupled MHD ion-chemistry model to analyze previously unpublished Giotto High Intensity Ion Mass Spectrometer (HIS-IMS) data. In this way we study the major species, but we also try to match s…
Density waves in Cassini UVIS stellar occultations. 1. The Cassini Division
Sremčević, M.; Colwell, J. E.; Cooney, J. H. +1 more
We analyze density waves in the Cassini Division of Saturn's rings revealed by multiple stellar occultations by Saturn's rings observed with the Cassini Ultraviolet Imaging Spectrograph. The dispersion and damping of density waves provide information on the local ring surface mass density and viscosity. Several waves in the Cassini Division are on…
The rotation of Janus and Epimetheus
Burns, Joseph A.; Thomas, Peter C.; Tiscareno, Matthew S.
Epimetheus, a small moon of Saturn, has a rotational libration (an oscillation about synchronous rotation) of 5.9°±1.2°, placing Epimetheus in the company of Earth's Moon and Mars' Phobos as the only natural satellites for which forced rotational libration has been detected. The forced libration is caused by the satellite's slightly eccentric orbi…