The discovery and dynamical evolution of an object at the outer edge of Saturn’s A ring

Murray, C. D.; Cooper, Nicholas J.; Williams, J. A. Gareth; Attree, Nicholas; Boyer, Jeffrey S.

doi:10.1016/j.icarus.2014.03.024

Cited by 15 publications

(15 citation statements)

References 16 publications

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“…In (Spitale and Porco(2010)), we identified at least 2 non-periodic perturbations (referred to as "spikes") in the B-ring edge that moved at Keplerian rates, suggesting the presence of mass concentrations internal to the ring, close enough to the edge to produce observable radial anomalies. A similar disturbance had also been noted at the A-ring edge (Spitale and Porco(2009)), and more recently an object has been directly imaged on that edge (Murray et al(2014)). The irregular appearance of the Huygens ringlet suggests the presence of many such mass inhomogeneities.…”

Section: Irregular Structuresupporting

confidence: 62%

The shape of Saturn’s Huygens ringlet viewed by Cassini ISS

Spitale¹,

Hahn²

2016

Icarus

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Section: Irregular Structuresupporting

confidence: 62%

The shape of Saturn’s Huygens ringlet viewed by Cassini ISS

Spitale¹,

Hahn²

2016

Icarus

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“…These migrating propeller-shaped structures (85), an analogy for protoplanets forming in a planetary nebula, were followed during the mission. Cassini also witnessed signs of the possible formation of a new moon at the outer edge of Saturn's A ring (86).…”

Section: Ringsmentioning

confidence: 99%

Cassini-Huygens’ exploration of the Saturn system: 13 years of discovery

Spilker

2019

Science

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The Cassini-Huygens mission to Saturn provided a close-up study of the gas giant planet, as well as its rings, moons, and magnetosphere. The Cassini spacecraft arrived at Saturn in 2004, dropped the Huygens probe to study the atmosphere and surface of Saturn’s planet-sized moon Titan, and orbited Saturn for the next 13 years. In 2017, when it was running low on fuel, Cassini was intentionally vaporized in Saturn’s atmosphere to protect the ocean moons, Enceladus and Titan, where it had discovered habitats potentially suitable for life. Mission findings include Enceladus’ south polar geysers, the source of Saturn’s E ring; Titan’s methane cycle, including rain that creates hydrocarbon lakes; dynamic rings containing ice, silicates, and organics; and Saturn’s differential rotation. This Review discusses highlights of Cassini’s investigations, including the mission’s final year.

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“…We showed that the object Peggy recently discovered at the ring edge (Murray et al 2014) is strongly perturbed by the Janus 7:6 LER (when Janus is on its inner leg of its libration motion), but not currently perturbed by any CER, with fitted semi-major axes just outside one of the four chaotic radial zones ( Figure 6). The model presented suggests that the periodic CER/LER perturbations due to the co-orbital moons may help to form objects at the ring edge from particles that move outwards.…”

Section: Discussionmentioning

confidence: 74%

The dynamics of the outer edge of Saturn’s A ring perturbed by the satellites Janus and Epimetheus

Araújo

Renner

Cooper

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present an analytical model to study the dynamics of the outer edge of Saturn's A ring. The latter is influenced by 7:6 mean motion resonances with Janus and Epimetheus. Because of the horseshoe motion of the two co-orbital moons, the ring edge particles are alternately trapped in a corotation eccentricity resonance (CER) or a Lindblad eccentricity resonance (LER). However, the resonance oscillation periods are longer than the four-year interval between the switches in the orbits of Janus and Epimetheus. Averaged equations of motion are used, and our model is numerically integrated to describe the effects of the periodic sweeping of the 7:6 CERs and LERs over the ring edge region. We show that four radial zones (ranges km) are chaotic on decadal timescales, within which particle semi-major axes have periodic changes due to partial libration motions around the CER fixed points. After a few decades, the maximum variation of semi-major axis is about eleven (resp. three) kilometres in the case of the CER with Janus (resp. Epimetheus). Similarly, particle eccentricities have partial oscillations forced by the LERs every four years. For initially circular orbits, the maximum eccentricity reached is ∼ 0.001. We apply our work to "Peggy", an object recently discovered at the ring edge (Murray et al. 2014), confirming that it is strongly perturbed by the Janus 7:6 LER. The CER has currently no effect on that body, nevertheless the fitted semi-major axes are just outside the chaotic zone of radial range 136756-136768 km.

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The discovery and dynamical evolution of an object at the outer edge of Saturn’s A ring

Cited by 15 publications

References 16 publications

The shape of Saturn’s Huygens ringlet viewed by Cassini ISS

The shape of Saturn’s Huygens ringlet viewed by Cassini ISS

Cassini-Huygens’ exploration of the Saturn system: 13 years of discovery

The dynamics of the outer edge of Saturn’s A ring perturbed by the satellites Janus and Epimetheus

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