Geology Reports⌕ Search
Home/Archive/USGS

USGS · 70022477

Perturbations to Saturn's F-ring strands at their closest approach to Prometheus

Winter S.M. Giuliatti·C.D. Murray·M. Gordon
View original source ↗Export metadata ↓

Abstract

The strange morphology of the F ring of Saturn is thought to be caused by the perturbing effects of two close satellites, Prometheus and Pandora. The F ring and the satellites also experience periodic close encounters as a result of differential precession arising from Saturn's oblateness. Using the orbits of the F-ring strands derived by Murray et al. (1997, Icarus 129, 304-316) the behaviour of the ring particles at their closest approach to Prometheus is analysed using numerical simulations. The results show that a gap and a wave are formed in the ring at each encounter with the satellite. However, the gap is expected to have a short lifetime due to keplerian shear.

Explore related subjects

Planetary and Space ScienceArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Winter S.M. Giuliatti, C.D. Murray, M. Gordon. 2000. Perturbations to Saturn's F-ring strands at their closest approach to Prometheus. https://doi.org/10.1016/s0032-0633(00)00009-x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2019

The compositions of the lunar crust and upper mantle: Spectral analysis of the inner rings of lunar impact basins

The innermost ring in impact basins exposes material originating from various depths, and can be used to study the composition of the lunar crust with depth. In this study, we conduct quantitative mineralogical analyses of the innermost ring in 13 lunar impact basins using reflectance data from the Kaguya Multiband Imager and radiative transfer modeling. We use results from recent hydrocode modeling to calculate the depth of origin of the material exposed by the innermost rings. We find that the most abundant rock type on the innermost ring of most basins is anorthosite. The mafic assemblages are dominated by olivine in some cases, but most often by pyroxene. The impact modeling suggests that the innermost ring material was excavated from a wide range of depths. Here we focus on two mean depths: a crustal component and a mantle component. The crustal component largely dominates the innermost ring material, and the mantle component is present on the innermost ring of 9 of the basins we studied. On these 9 rings, the abundance of low-calcium pyroxene decreases with the proportion of crustal component, suggesting a dominantly mantle origin. However, as we do not detect exposures of ultramafic material, such mantle material is possibly present at the sub-pixel scale (<62 m). This quantitative study reassesses the composition of the lunar crust and upper mantle, which is of great importance for understanding the formation of the Moon.

Planetary and Space Science↗
USGS2018

Interoperability in planetary research for geospatial data analysis

For more than a decade there has been a push in the planetary science community to support interoperable methods for accessing and working with geospatial data. Common geospatial data products for planetary research include image mosaics, digital elevation or terrain models, geologic maps, geographic location databases (e.g., craters, volcanoes) or any data that can be tied to the surface of a planetary body (including moons, comets or asteroids). Several U.S. and international cartographic research institutions have converged on mapping standards that embrace standardized geospatial image formats, geologic mapping conventions, U.S. Federal Geographic Data Committee (FGDC) cartographic and metadata standards, and notably on-line mapping services as defined by the Open Geospatial Consortium (OGC). The latter includes defined standards such as the OGC Web Mapping Services (simple image maps), Web Map Tile Services (cached image tiles), Web Feature Services (feature streaming), Web Coverage Services (rich scientific data streaming), and Catalog Services for the Web (data searching and discoverability). While these standards were developed for application to Earth-based data, they can be just as valuable for planetary domain. Another initiative, called VESPA (Virtual European Solar and Planetary Access), will marry several of the above geoscience standards and astronomy-based standards as defined by International Virtual Observatory Alliance (IVOA). This work outlines the current state of interoperability initiatives in use or in the process of being researched within the planetary geospatial community.

Planetary and Space Science↗
USGS2018

Crater density differences: Exploring regional resurfacing, secondary crater populations, and crater saturation equilibrium on the moon

The global population of lunar craters >20 km in diameter was analyzed by Head et al., (2010) to correlate crater distribution with resurfacing events and multiple impactor populations. The work presented here extends the global crater distribution analysis to smaller craters (5–20 km diameters, n = 22,746). Smaller craters form at a higher rate than larger craters and thus add granularity to age estimates of larger units and can reveal smaller and younger areas of resurfacing. An areal density difference map generated by comparing the new dataset with that of Head et al., (2010) shows local deficiencies of 5–20 km diameter craters, which we interpret to be caused by a combination of resurfacing by the Orientale basin, infilling of intercrater plains within the nearside highlands, and partial mare flooding of the Australe region. Chains of 5–30 km diameter secondaries northwest of Orientale and possible 8–22 km diameter basin secondaries within the farside highlands are also distinguishable. Analysis of the new database indicates that craters 57–160 km in diameter across much of the lunar highlands are at or exceed relative crater densities of R = 0.3 or 10% geometric saturation, but nonetheless appear to fit the lunar production function. Combined with the observation that small craters on old surfaces can reach saturation equilibrium at 1% geometric saturation (Xiao and Werner, 2015), this suggests that saturation equilibrium is a size-dependent process, where large craters persist because of their resistance to destruction, degradation, and resurfacing.

Planetary and Space Science↗