Simulations of Enceladus' Tendril Features
Abstract
We simulate the large-scale, sinuous structures observed in CassiniISS images of the E ring near Enceladus, dubbed 'tendrils', bynumerically integrating the trajectories of particles launched fromthe sources of geysers along the "tiger stripe" fractures crossingEnceladus's South Polar Terrain (SPT) . In addition to gravitationalforces due to Saturn and Enceladus, we include electromagnetic forcesdue to Saturn's magnetic and electric fields, and charging currentsarising from particle interactions with magnetospheric plasma andSolar UV radiation. These simulations are used to produce syntheticimages which are then compared to Cassini ISS tendril images taken in2006 and 2013.For each image, we follow into the E ring the trajectories ofparticles erupting from the 36 most active geysers, using the 3Dconfiguration and strength information reported in Porco et al., 2014and the velocity distribution in Ingersoll and Ewald, 2011. This setaccounts for more than 50% of the total measured activity and alsoprovides a good sampling of geyser orientations. We find that specificsubsets of geysers appear to be the sources of identifiable tendrilfeatures present in the images, and that none of the tendril featurescan be reproduced by low eccentricity E ring particles, We concludethat the tendrils are produced by geyser particles recently eruptedfrom Enceladus.Finally, we find indications of the geysers' time variability in thechanging appearance of the tendrils from one observation to the next.We have been able to reproduce these changes in a crude way by varyingthe number of particles ejected from the sources with time, accordingto the brightness variation model presented in Nimmo et al. 2014.Nimmo et al., 2014, AJ, 148, 46.Porco et al., 2014, AJ, 148, 45.Ingersoll and Ewald, 2011, Icarus, 216, 492
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2014
- Bibcode:
- 2014AGUFM.P51F..10M
- Keywords:
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- 5215 Origin of life;
- PLANETARY SCIENCES: ASTROBIOLOGY;
- 6282 Enceladus;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS