Lick
Observatory, Mt.Hamilton, California
W.
M. Keck Observatory,
Hawaii
|
|
|
|
|
Lick
Observatory, Mt.Hamilton, California
|
W.
M. Keck Observatory,
Hawaii
|
URANUS' RINGS IN 2004
URANUS' RINGS ARE CLOSING UP Near infrared image of Uranus' ring system taken with AO on Keck II between 2000 and 2004, (mostly) at K'-band (2.2 micron). At this wavelength, methane and hydrogen gases in Uranus' atmosphere absorb most sunlight falling on the planet, so not much is reflected back into space. Hence, Uranus itself is very dark, and the rings are clearly visible. This series of images shows the change in ring inclination angle as the rings are gradually closing up (we will pass through Uranus' ring plane in 2007). One can also see the gradual improvement in the Keck AO system. (de Pater, I., S.G. Gibbard and H.B. Hammel, 2005. Evolution of the Dusty Rings of Uranus. Icarus, 180, 186-200.) See Press Release DPS 2004
URANUS' RINGS IN 2004: ZETA RING Near infrared image of Uranus' ring system taken with AO on Keck II on 3-9 July 2004 at K'-band (2.2 micron). At this wavelength, methane and hydrogen gases in Uranus' atmosphere absorb most sunlight falling on the planet, so not much is reflected back into space. Hence, Uranus itself is very dark, and the rings are clearly visible. The individual rings are clearly recognized, as well as a sheet of material interior to rings 456. This is the first image since the Voyager encounter in 1986 that reveals a broad faint dusty ring interior to the main rings, that could be related to the 1986U2R ring discovered by Voyager. More detailed modeling of these images also reveals the presence of dust in between the main rings, with a spatial distribution distinctly different than during the Voyager era. (de Pater, I., S.G. Gibbard and H.B. Hammel, 2005. Evolution of the Dusty Rings of Uranus. Icarus, 180, 186-200.)
