Fates of ejecta from co-orbital satellites: Tethys, Telesto, and Calypso
Abstract
Unique in the Solar system, the crowded satellite system of Saturn has three sets of moons sharing essentially the same orbits: the two small co-orbitals Janus and Epimetheus, Tethys with its Trojan companions Telesto and Calypso, and Dione with its Trojans Helene and tiny Polydeuces. We have used the SWIFT integrator package to simulate the fates of impact ejecta from Tethys, Telesto, and Calypso in order to study the exchange of material among co-orbitals. Our simulations include all nine of Saturn's major satellites as well as Telesto, Calypso, Helene, and Polydeuces. Of primary spalls ejected into planetocentric orbit from Tethys' two largest craters (Odysseus on its leading side and Penelope on its trailing side), we find that about 90 percent eventually re-impact Tethys. In comparison, some 10 percent hit other major satellites, but on the order of 0.1 percent strike Tethys' Trojan companions Telesto or Calypso, consistent with their geometric cross-sections. For ejecta from Telesto and Calypso, we use slower launch speeds more appropriate for their softer regolith surfaces. We find that the rubble falls into several distinct categories, depending on both the speed and direction of launch. One consequence is the exchange of material between Telesto and Calypso. We will describe how the fates of their ejecta depend on launch velocity as well as other novel phenomena of co-orbital ejecta.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.P51C1146D
- Keywords:
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- 5420 PLANETARY SCIENCES: SOLID SURFACE PLANETS / Impact phenomena;
- cratering;
- 6022 PLANETARY SCIENCES: COMETS AND SMALL BODIES / Impact phenomena;
- 6035 PLANETARY SCIENCES: COMETS AND SMALL BODIES / Orbital and rotational dynamics;
- 6280 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS / Saturnian satellites