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On the nature of particles in Saturn's spokes
Author(s) -
Thomsen M. F.,
Goertz C. K.,
Northrop T. G.,
Hill J. R.
Publication year - 1982
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl009i004p00423
Subject(s) - limit (mathematics) , physics , charge (physics) , saturn , particle (ecology) , yield (engineering) , atomic physics , mechanics , astrophysics , planet , geology , quantum mechanics , thermodynamics , mathematical analysis , oceanography , mathematics
An observed deviation of the angular velocity of spoke features from the Keplerian value can yield the charge to mass ratio of spoke particles. Published observations of spoke motion are consistent with q/m in the neighborhood of −10 coul/kg. Since a lower limit on q is one electronic charge, this value yields a lower limit to the size of spoke particles of about 10 −2 µm. The criteria for electrostatically ejecting small particles from larger parent bodies indicate an upper limit of about 10³ m for the parent bodies. Stability of the grains against electrostatic disruption or field emission yields an upper limit of ∼3 µm for the spoke particle size and leads to the conclusion that the spoke particles must consist of material which is stronger than loose dust balls.