The Anthe Arc

 

Cassini images reveal the existence of a faint arc of material orbiting

with Saturn's small moon Anthe.

 

 

The moon is moving downward and to the right in this perspective. In this

image, most of the visible material in the arc lies ahead of Anthe (2

kilometers, or 1 mile across) in its orbit. However, over time the moon

drifts slowly back and forth with respect to the arc. The arc extends over

about 20 degrees in longitude (about 5.5 percent of Anthe's orbit) and

appears to be associated with a gravitational resonance caused by the moon

Mimas. Micrometeoroid impacts on Anthe are the likely source of the arc

material. The orbit of Anthe lies between the larger moons Mimas and

Enceladus. Anthe shares this region with two other small moons, Pallene (4

kilometers, or 3 miles across) and Methone (3 kilometers, or 2 miles

across). Methone also possesses an arc (see PIA11102), while Pallene is known

to orbit within a faint, complete ring of its own (see PIA08328).

 

 

Cassini imaging scientists believe the process that maintains the Anthe

and Methone arcs is similar to that which maintains the arc in the G ring

(see PIA08327). The general brightness of the image (along with the faint

horizontal banding pattern) results from the long exposure time of 32

seconds required to capture the extremely faint ring arc and the

processing needed to enhance its visibility (which also enhances the

digital background noise in the image). The image was digitally processed

to remove most of the background noise. The long exposure also produced

star trails in the background. This view looks toward the un-illuminated

side of the rings from about 3 degrees above the ringplane.

 

 

The image was taken in visible light with the Cassini spacecraft

narrow-angle camera on July 3, 2008. The view was obtained at a distance

of approximately 1.2 million kilometers (739,000 miles) from Anthe and at

a sun-Anthe-spacecraft, or phase, angle of 12 degrees. Image scale is 7

kilometers (4 miles) per pixel.

 

 

The Cassini-Huygens mission is a cooperative project of NASA, the European

Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,

a division of the California Institute of Technology in Pasadena, manages

the mission for NASA's Science Mission Directorate, Washington, D.C. The

Cassini orbiter and its two onboard cameras were designed, developed and

assembled at JPL. The imaging operations center is based at the Space

Science Institute in Boulder, Colo.

 

 

For more information about the Cassini-Huygens mission visit

saturn.jpl.nasa.gov. The Cassini imaging team

homepage is at ciclops.org.

 

credit: NASA/JPL/Space Science Institute

Done