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Title: The Ring System of Uranus: Flat as a Pancake, Sprinkled with Dust

Abstract

We present a high quality image of the uranian ring system, obtained in July 2004 at 2.2 {micro}m with the adaptive optics camera NIRC2 on the Keck II telescope. Using these data, we report the first ground-based image of the ring 1986U2R, seen only once before by the Voyager spacecraft. We show that this ring extends inward to {approx} 7000 km above the Uranus cloud deck. Its VIF (total vertically integrated I/F) is {approx} 100 m. We further detected narrow sheets of dust in between the {delta} and {epsilon} rings, and in between rings 4 and {alpha}, with a VIF of 14 and 20 m, respectively. Surprisingly, we find that the particles in Uranus' 9 main rings are distributed within a mono-layer, rather than the usually adopted poly-layer model. We come to this conclusion via a comparison of the VIF as derived from our 2003 data at a ring opening angle B {approx} 18{sup o} (from Gibbard et al. 2004) with those derived in this paper at B {approx} 11{sup o}. We show that the VIF increases approximately as 1/sinB at the ring ansae, but is independent of sinB in front of the disk. This combination of factors can onlymore » be explained if the particles in Uranus' rings are distributed in a mono-layer, a configuration which makes the uranian system unique amongst the giant planets.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
875942
Report Number(s):
UCRL-JRNL-211287
TRN: US200604%%254
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Icarus
Additional Journal Information:
Journal Volume: 180; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CAMERAS; CLOUDS; CONFIGURATION; DUSTS; OPENINGS; OPTICS; PLANETS

Citation Formats

de Pater, I, Gibbard, S G, and Hammel, H B. The Ring System of Uranus: Flat as a Pancake, Sprinkled with Dust. United States: N. p., 2005. Web.
de Pater, I, Gibbard, S G, & Hammel, H B. The Ring System of Uranus: Flat as a Pancake, Sprinkled with Dust. United States.
de Pater, I, Gibbard, S G, and Hammel, H B. 2005. "The Ring System of Uranus: Flat as a Pancake, Sprinkled with Dust". United States. https://www.osti.gov/servlets/purl/875942.
@article{osti_875942,
title = {The Ring System of Uranus: Flat as a Pancake, Sprinkled with Dust},
author = {de Pater, I and Gibbard, S G and Hammel, H B},
abstractNote = {We present a high quality image of the uranian ring system, obtained in July 2004 at 2.2 {micro}m with the adaptive optics camera NIRC2 on the Keck II telescope. Using these data, we report the first ground-based image of the ring 1986U2R, seen only once before by the Voyager spacecraft. We show that this ring extends inward to {approx} 7000 km above the Uranus cloud deck. Its VIF (total vertically integrated I/F) is {approx} 100 m. We further detected narrow sheets of dust in between the {delta} and {epsilon} rings, and in between rings 4 and {alpha}, with a VIF of 14 and 20 m, respectively. Surprisingly, we find that the particles in Uranus' 9 main rings are distributed within a mono-layer, rather than the usually adopted poly-layer model. We come to this conclusion via a comparison of the VIF as derived from our 2003 data at a ring opening angle B {approx} 18{sup o} (from Gibbard et al. 2004) with those derived in this paper at B {approx} 11{sup o}. We show that the VIF increases approximately as 1/sinB at the ring ansae, but is independent of sinB in front of the disk. This combination of factors can only be explained if the particles in Uranus' rings are distributed in a mono-layer, a configuration which makes the uranian system unique amongst the giant planets.},
doi = {},
url = {https://www.osti.gov/biblio/875942}, journal = {Icarus},
number = 1,
volume = 180,
place = {United States},
year = {2005},
month = {2}
}