UNRAVELING THE STRANDS OF SATURN F-RING

Several high-resolution Voyager 2 images of Saturn's F ring show that it is composed of at least four separate, non-intersecting strands ext ending similar to 45 degrees in longitude. Voyager 1 images show that the two brightest strands appear to intersect, giving rise to a ''brai ded'' morphology. From a study of all available Voyager images the det ectable radial structure is cataloged and reviewed. Previous indicatio ns that there is fine material interior to the orbit of the F ring are confirmed. Evidence is presented that a model of four strands with co mparable eccentricities and nearly aligned perichrones is consistent w ith all the Voyager observations. The observed perichrone offset of th e two brightest strands suggests a minimum radial separation of simila r to 20 km, which implies intersection of these strands when their fin ite radial widths are taken into account. The longitude range of such an intersection includes that observed in the Voyager 1 ''braid'' imag es. The proximity of these two strands at some longitudes may account for the apparent differences in the ring between the Voyager encounter s, as well as provide a source for the short-lived features detected i n the Hubble Space Telescope images of the F ring. There is no evidenc e that the locations of the individual strands are determined by reson ant perturbations with known satellites. It is proposed that the radia l structure is formed by the localized action of small satellites orbi ting within the strand region. (C) 1997 Academic Press.