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Unmanned Spaceflight.com _ Uranus and Neptune _ Neptune's ring arcs

Posted by: PhilCo126 May 11 2006, 09:35 PM

I'm still amazed by the beauty of Neptune's ring arcs ... about time someone finds an explanation for those ?

Posted by: BruceMoomaw May 12 2006, 01:42 AM

They're supposed to be entirely due to a complex interaction with a single one of Neptune's tiny inner moons, Larissa. I know virtually no details, but give me a little time and I'll dig up more on it (*sigh*).

Posted by: Phil Stooke May 12 2006, 02:07 AM

Galatea, Bruce:

Porco, C. C. 1991. An explanation for Neptune's ring arcs. Science 253, 995-1001.

Abstract
The Voyager mission revealed a complex system of rings and ring arcs around Neptune and uncovered six new satellites, four of which occupy orbits well inside the ring region. Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the ring arcs, a perturbation attributable to the nearby satellite Galatea. Moreover, the arcs appear to be azimuthally confined by a resonant interaction with the same satellite, yielding a maximum spread in ring particle semimajor axes of 0.6 kilometer and a spread in forced eccentricities large enough to explain the arc's 15-kilometer radial widths. Additional ring arcs discovered in the course of this study give further support to this model.

Phil

Posted by: PhilCo126 May 12 2006, 08:07 AM

Thanks !

Posted by: BruceMoomaw May 12 2006, 11:17 AM

Yep, Galatea...Sorry. (I plumb forgot that Larissa is one of Neptune's biggest moons...)

I've spent a while last night sifting through my stored Web documents on the Neptune system and found a few short items relating to both the rings arcs and the new theory about Tritan's capture -- but I haven't even gotten around to rereading them yet. More tomorrow, I hope.