Adaptive Optics Observations of Saturn's Ring Plane Crossing in August 1995

Roddier, F.; Roddier, C.; Brahic, A.; Dumas, Christophe; Graves, J. E.; Northcott, M. J.; Owen, Tobias

doi:10.1006/icar.1999.6251

Cited by 9 publications

(7 citation statements)

References 17 publications

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“…11 is offset in geometric albedo by −0.2 for clarity. The Buratti albedo is consistent with Roddier et al (2000), who found 0.78 ± 0.10 at J and 0.55 ± 0.03 at H, also for the trailing hemisphere, but not with the value of 0.66 ± 0.04 at K found by Momary et al (2000). Both spectra clearly show the presence of crystalline H 2 O ice, with a prominent 1.65 µm absorption band.…”

Section: Mimassupporting

confidence: 86%

A spectroscopic study of the surfaces of Saturn's large satellites: HO ice, tholins, and minor constituents

Cruikshank¹,

Owen²,

Ore³

et al. 2005

Icarus

100

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We present spectra of Saturn's icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, and Hyperion, 1.0-2.5 µm, with data extending to shorter (Mimas and Enceladus) and longer (Rhea and Dione) wavelengths for certain objects. The spectral resolution (R = λ/ λ) of the data shown here is in the range 800-1000, depending on the specific instrument and configuration used; this is higher than the resolution (R = 225 at 3 µm) afforded by the Visual-Infrared Mapping Spectrometer on the Cassini spacecraft. All of the spectra are dominated by water ice absorption bands and no other features are clearly identified. Spectra of all of these satellites show the characteristic signature of hexagonal H 2 O ice at 1.65 µm. We model the leading hemisphere of Rhea in the wavelength range 0.3-3.6 µm with the Hapke and the Shkuratov radiative transfer codes and discuss the relative merits of the two approaches to fitting the spectrum. In calculations with both codes, the only components used are H 2 O ice, which is the dominant constituent, and a small amount of tholin (Ice Tholin II). Tholin in small quantities (few percent, depending on the mixing mechanism) appears to be an essential component to give the basic red color of the satellite in the region 0.3-1.0 µm. The quantity and mode of mixing of tholin that can produce the intense coloration of Rhea and other icy satellites has bearing on its likely presence in many other icy bodies of the outer Solar System, both of high and low geometric albedos. Using the modeling codes, we also establish detection limits for the ices of CO 2 (a few weight percent, depending on particle size and mixing), CH 4 (same), and NH 4 OH (0.5 weight percent) in our globally averaged spectra of Rhea's leading hemisphere. New laboratory spectral data for NH 4 OH are presented for the purpose of detection on icy bodies. These limits for CO 2 , CH 4 , and NH 4 OH on Rhea are also applicable to the other icy satellites for which spectra are presented here. The reflectance spectrum of Hyperion shows evidence for a broad, unidentified absorption band centered at 1.75 µm.

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Section: Mimassupporting

confidence: 86%

A spectroscopic study of the surfaces of Saturn's large satellites: HO ice, tholins, and minor constituents

Cruikshank¹,

Owen²,

Ore³

et al. 2005

Icarus

100

View full text Add to dashboard Cite

show abstract

“…In the majority of the images, however, the predicted location is empty of potentially interfering material, and yet S11, S12, and S13 are not seen. One possible reason for our nondetections, suggested by Roddier et al (2000), is the difference in exposure times of the two data sets. Because HST exposures were 100 s long and the CFHT exposures were 15 s, the apparent clump motion may have resulted in a blur which lowered the signal-to-noise in the HST images.…”

Section: Other Data Setsmentioning

confidence: 93%

HST Observations of Saturnian Satellites during the 1995 Ring Plane Crossings

McGhee

Nicholson

French

et al. 2001

Icarus

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“…If we assume that it has the same orbital plane parameters as the F ring, it should have disappeared from images taken between 14:10 and 15:30 UT. During this time, at least two groups were observing the rings, with the HST (Nicholson et al 1996) and with a ground-based adaptive optics (AO) system (Roddier et al 2000). The HST team reports two detections of S5 on the west ansa, obtained at 13:47 and 13:54 UT (included in Fig.…”

Section: Observational Implicationsmentioning

confidence: 99%

“…During the most recent ring-plane crossing in 1995-1996, several bodies that are assumed to be clumps within the F ring were discovered by various observers (Bosh and Rivkin 1996, Nicholson et al 1996, Roddier et al 2000, McGhee et al 2001. Thus, an accurate kinematic model for the F ring is important for goals such as determining the dynamical relationships between the ring and nearby satellites, and whether the objects seen during the 1995 ring-plane crossing reside within this ring.…”

Section: Introductionmentioning

confidence: 97%