Other
Scientific paper
May 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agusm.p31a..02b&link_type=abstract
American Geophysical Union, Spring Meeting 2008, abstract #P31A-02
Other
5759 Rings And Dust, 6265 Planetary Rings, 6275 Saturn
Scientific paper
The Cassini Ultraviolet Imaging Spectrograph (UVIS) offers the opportunity to analyze the water ice properties of Saturn's rings in the ultraviolet spectral regime. The rings consist mostly of water ice; however past work in the visible and infrared spectral regimes has shown small amounts of non-water-ice contaminants to be present with regional variations in contamination across the rings. Determining the fractional composition of the rings plays into the larger context of answering questions concerning the amount of space weathering and age of the rings. Water ice exhibits a strong absorption feature shortward of 170 nm, which is observed by UVIS. We analyze spectra from many observations to help constrain ring particle properties and their variation with position in the rings. We use a Hapke bidirectional reflectance model to model spectra at different ring radii. The parameters of this model include the single scattering albedo of ring particles and a size parameter indicative of the path length of photons through the medium. This may represent the mean spacing between contaminants in a water-ice matrix, the size of individual ice grains on the surface of larger ring particles, or the distance between cracks or other scattering surfaces in the particles. The size parameter controls the wavelength of the water ice absorption feature. A larger size parameter provides a longer path length of absorbing ice and the absorption feature moves to longer wavelengths. Constraining grain sizes can give insight to the microscopic structural properties of ring particles. The overall brightness of the rings depends on the optical depth that the rings present both to the incident light and the emitted light. Because the ring particles are not randomly distributed within the rings but are instead clustered in elongated self-gravity wakes, modeling the photometric brightness requires a detailed ray-tracing model with a realistic distribution of ring particles. The size parameter can be determined from the observed location of the water-ice absorption edge in UVIS spectra. We find that the retrieved size parameter exhibits radial variations with a peak occurring in the Cassini division that decreases radially in both directions and then peaks again in the inner B ring region. Here we present results showing the variation across the rings of ring spectral properties in the ultraviolet.
Bradley Eric Todd
Colwell Joshua E.
Esposito W. L. W. L.
No associations
LandOfFree
Composition and Size Properties of Saturn's Rings Determined From Ultraviolet Measurements Made by the Cassini Ultraviolet Imaging Spectrograph does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Composition and Size Properties of Saturn's Rings Determined From Ultraviolet Measurements Made by the Cassini Ultraviolet Imaging Spectrograph, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition and Size Properties of Saturn's Rings Determined From Ultraviolet Measurements Made by the Cassini Ultraviolet Imaging Spectrograph will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1397540