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We present a comprehensive solution for the geometry of Saturn’s ring system, based on orbital fits to an extensive set of occultation observations of 122 individual ring edges and gaps. We begin with a restricted set of very high quality Cassini VIMS, UVIS, and RSS measurements for quasi-circular features in the C and B rings and the Cassini Division, and then successively add suitably weighted additional...
The eccentric Maxwell ringlet in Saturn’s C ring is home to a prominent wavelike structure that varies strongly and systematically with true anomaly, as revealed by nearly a decade of high-SNR Cassini occultation observations. Using a simple linear “accordion” model to compensate for the compression and expansion of the ringlet and the wave, we derive a mean optical depth profile for the ringlet and...
We have conducted a comprehensive survey of 22 sharp-edged ringlets and gaps in the Cassini Division of Saturn’s rings, making use of nearly 200 high-SNR stellar and radio occultation chords obtained by the Cassini VIMS, UVIS, and RSS instruments between 2005 and 2013. We measure eccentricities from as small as ae=80 m to nearly 30 km, free normal modes with amplitudes from ∼ 0.1 to 4.1 km, and detectable...
We present a comprehensive survey of sharp-edged features in Saturn’s C ring, using data from radio and stellar occultation experiments carried out by the Cassini spacecraft over a period of more than five years. Over 100 occultations are included in the combined data set, enabling us to identify systematic radial perturbations as small as 200m on the edges of ringlets and gaps. We systematically...
We present the results of six soundings of the atmosphere of Titan by the radio occultation technique using the Cassini spacecraft currently in orbit around Saturn. These occultations occurred during four separate targeted Titan encounters in both the Prime and Equinox missions of Cassini over 3years. They cover a wide range of latitude from 75°S to 79°N, split so that three soundings are in the northern...
We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31–34°S near the surface, and the fourth at 52.8°S. Temperature–altitude profiles for all four occultation soundings are presented, and compared with the results of the Voyager 1 radio...
Cassini radio science experiments have provided multiple occultation optical depth profiles of Saturn's rings that can be used in combination to analyze density waves. This paper establishes an accurate procedure of inversion of the wave profiles to reconstruct the wave kinematic parameters as a function of semi-major axis, in the nonlinear regime. This procedure is established using simulated data...
From 378 Hubble Space Telescope WFPC2 images obtained between 1996–2004, we have measured the detailed nature of azimuthal brightness variations in Saturn's rings. The extensive geometric coverage, high spatial resolution (∼300 kmpx−1), and photometric precision of the UBVRI images have enabled us to determine the dependence of the asymmetry amplitude and longitude of minimum brightness on orbital...
As part of a long-term study of Saturn's rings, we have used the Hubble Space Telescope's (HST) Wide Field and Planetary Camera (WFPC2) to obtain several hundred high resolution images from 1996 to 2004, spanning the full range of ring tilt and solar phase angles accessible from the Earth. Using these multiwavelength observations and HST archival data, we have measured the photometric properties of...
Hubble Space Telescope (HST) Wide-Field Planetary Camera (WFPC2) observations at phase angles in the range α=0.26 o -6.4 o obtained at every opposition and near quadrature between October 1996 and December 2002 reveal the opposition effect of Enceladus. We present a photometric analysis of nearly 200 images obtained through the five broadband UVBRI filters (F336W, F439W, F555W, F675W,...
Saturn's narrow F ring is flanked by two nearby small satellites, Prometheus and Pandora, discovered in Voyager images taken in 1980 and 1981 , Icarus 53, 156-158). Observations with the Hubble Space Telescope (HST) during the ring plane crossings (RPX) of 1995 led to the unexpected finding that Prometheus was ~19 o behind its predicted orbital longitude, based on the Voyager ephemeris Science...
In May, August, and November 1995, Hubble Space Telescope (HST) observations during Saturn's ring-plane crossings allowed us to view saturnian satellites normally hidden to Earth-based observers in the glare of the rings. New measurements of Janus, Epimetheus, Prometheus, and Pandora have been combined to form revised orbital solutions using all three HST data sets. These measurements and orbit fits...
We present observations of three Neptune central flash events: the 20 August 1985 occultation of n39 from the European Southern Observatory (ESO), the 12 September 1988 occultation of N51 from Pic du Midi, and the 8 July 1989 occultation of N55 from ESO. From simultaneous fits to the three central flash lightcurves, we determine the shape of Neptune's limb, and show that winds near the 0.38-mbar level...
The 11 July 1992 occultation of Uranus by U103 (m K = 10.1) was observed using the 5-m Hale telescope on Palomar Mountain in California, the 4-m telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, and the nearby 2.2-m telescope at European Southern Observatory (ESO). All observations were taken using InSb aperture photometers andK(λ ∼ 2.2 μm) filters and provided high-quality...
We present observations of Saturn's central flash obtained from Palomar and McDonald Observatories during the 3 July 1989 occultation of 28 Sgr. As the star passed close to the geometric center of Saturn's shadow, the focusing of the incident starlight by the planet's atmosphere formed multiple stellar images along the limb which were detected in infrared images obtained at wavelengths of 3.9 (Palomar)...
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