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

Journal Article · Wed Feb 02 04:00:00 EST 2005 · Icarus

OSTI ID:875942

de Pater, I; Gibbard, S G; Hammel, H B

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.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 875942
• Report Number(s): UCRL-JRNL-211287
• Journal Information: Icarus, Journal Name: Icarus Journal Issue: 1 Vol. 180
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
CAMERAS
CLOUDS
CONFIGURATION
DUSTS
OPENINGS
OPTICS
PLANETS