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| Titel |
How the Enceladus dust plume forms Saturn's E ring |
| VerfasserIn |
S. Kempf, U. Beckmann, J. Schmidt |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250029036
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| Zusammenfassung |
| Before Cassini, dynamical models of Saturn’s E ring (Horanyi et al., 1992) failed to
reproduce its peculiar vertical structure inferred from earth-bound observations (de Pater et
al., 2004). After the discovery of an active ice-volcanism in the south pole terrain of Saturn’s
icy moon Enceladus the relevance of this particle source for the vertical ring structure was
swiftly recognised (Juhasz et al., 2007, Kempf et al., 2008). However, ad-hoc models for the
plume particle injection predict too a small vertical ring thickness and overestimate the
amount of the injected dust.
Here we report on numerical simulations of the particle ejection into the ring. We run a
large number of dynamical simulations including gravity and Lorentz force to investigate the
earliest phase of the ring particle life span. The evolution of electrostatic charge carried by the
initially uncharged grains is treated selfconsistently. Freshly ejected plume particles are
moving in almost circular orbits because Enceladus’ orbital speed exceeds the particles’
ejection speeds by far. Only a small number of the ejected grains survives against re-collision
with the moon after their first orbit. Thus, the flux and the size distribution of those
plume particles replenishing the E ring differs significantly from the size distribution
and flux in the plume itself. Our numerical simulations reproduce the vertical ring
profile measured by the Cassini dust instrument CDA (Kempf et al., 2008a) and it is
consistent with edge-on images obtained by the Cassini camera ISS (Burns et al., 2005). |
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