The speed distribution of Saturn's E ring particles
Abstract
The dynamics of Saturn's diffuse E rings has turned out to be much more complicated as we have thought until Cassini's arrival. Key for obtaining insight into the ring particle dynamics is good knowledge of the particles' orbital elements, which in turn can be derived from the grain speeds. Impact ionization dust detectors such as Cassini's Cosmic Dust Analyzer (CDA) (Srama et al. 2004) are capable to constrain the grains' impact speed from the impact plasma evolution time scale with an uncertainty factor of about 2 (Auer 2001). While this so-called "rise time" method is adequate to differentiate various dust populations such as interplanetary dust particles (IDP), beta meteoroids, or interstellar dust (ISD), its accuracy is often not sufficient to investigate the dynamics of a population itself. All attempts to derive the speeds with sufficient accuracy from the E ring dust data obtained by CDA have failed so far.
However, it has been realized early that the impact mass spectra of the ring's ice particles obtained by CDA's mass spectrometer show a strong dependence on the impact speed. Here we present a method to derive the impact speed of water ice particles from their corresponding impact mass spectra. This method allows us for the first time to derive the distribution of ring particle speeds as function of the radial distance to Saturn.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P53E3012K
- Keywords:
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- 2129 Interplanetary dust;
- INTERPLANETARY PHYSICSDE: 6213 Dust;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6245 Meteors;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 6265 Planetary rings;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS