Keck Adaptive Optics Images of Uranus and Its Rings

✍ Scribed by Imke de Pater; S.G. Gibbard; B.A. Macintosh; H.G. Roe; D.T. Gavel; C.E. Max

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 748 KB
• Volume: 160
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2002.6966

✦ Synopsis

We present adaptive optic images of Uranus obtained with the 10-m W. M. Keck II telescope in June 2000, at wavelengths between 1 and 2.4 µm. The angular resolution of the images is ∼0.06-0.09 . We identified eight small cloud features on Uranus's disk, four of which were in the northern hemisphere. The latter features are ∼1000-2000 km in extent and located in the upper troposphere, above the methane cloud, at pressures between 0.5 and 1 bar. Our data have been combined with HST data by Hammel et al. (2001, Icarus 153, 229-235); the combination of Keck and HST data allowed derivation of an accurate wind velocity profile. Our images further show Uranus's entire ring system: the asymmetric ring, as well as the three groups of inner rings (outward from Uranus): the rings 6 + 5 + 4, α + β, and the η + γ + δ rings. We derived the equivalent I/F width and ring particle reflectivity for each group of rings. Typical particle albedos are ∼0.04-0.05, in good agreement with HST data at 0.9 µm.