Nature 337, 340 - 343 (26 January 1989); doi:10.1038/337340a0

Orbital evolution of circumplanetary dust by resonant charge variations

Joseph A. Burns^* & Les Schaffer^†

Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, New York 14853, USA
^*Also at the Department of Astronomy, Cornell University, Ithaca, New York 14853, USA.
^†Also at the Astronomy Unit, Queen Mary College, London El 4NS, UK.

Vast ethereal rings composed of micrometre-sized particles have been detected about the three giant planets so far visited by Voyager. Jupiter's diffuse halo, main ring¹ and gossamer ring² are visible because of the dust they contain. Small particles are also important constituents of Saturn's tenuous outlying rings: the contorted slender F ring³, the G ring^4–6 and the extensive E ring^6,7. At Uranus, dust was discerned by imaging⁸ amidst, as well as inwards of, the nine previously known narrow rings; plasma measurements^9,10 suggest that micrometre grains are also present in an orbit of 4.4 times the planet's radius, where Voyager 2 pierced the planet's equatorial plane. Here we identify an orbital evolution mechanism for gravitationally dominated dust that may tem-porarily overwhelm other processes, and we derive evolution rates that agree with numerical integrations; we also indicate briefly how this process could affect the location of the faint rings evident today.

References

1.	Showalter, M. R., Burns, J. A., Cuzzi, J. N. & Pollack, J. B. Icarus 69, 458−498 (1987). | Article |
2.	Showaller, M. R., Burns, J. A., Cuzzi, J. N. & Pollack, J. B. Nature 316, 526−528 (1985). | Article | PubMed | ISI | ChemPort |
3.	Ockert, M. E., Pollack, J. B., Showalter, M. R. & Doyle, L. R. Bull. Am. astr. Soc. 19, 883 (1987).
4.	Van Allen, J. A. J. geophys. Res. 88, 6911−6918 (1983). | ChemPort |
5.	Van Allen, J. A. J. geophys. Res. 92, 1153−1159 (1987).
6.	Burns, J. A., Showalter, M. R. & Morfill, G. E. in Planetary Rings (eds Greenberg, R. & Brahic, A.) 200−272 (Univ. of Arizona Press, Tucson, 1984).
7.	Pang, K. V., Voge, C. C., Rhoads, J. W. & Ajello, J. M. J. geophys. Res. 89, 9459−9470 (1984). | ChemPort |
8.	Smith, B. A. et al. Science 233, 43−64 (1986). | ISI |
9.	Meyer-Vernet, N., Aubier, M. G. & Pedersen, B. M. Geophys. Res. Lett. 13, 617−620 (1986).
10.	Gurnett, D. A. et al. J. geophys. Res. 92, 14949−14958 (1987).
11.	Schaffer, L. & Burns, J. A. J. geophys. Res. 92, 2264−2280 (1987).
12.	Mendis, D. A., Hill, J. R., Ip, W.-H., Goertz, C. K. & Grün, E. in Saturn (eds Gehrels T. & Matthews, M. S.) 546−589 (Univ. of Arizona Press, Tucson 1984).
13.	Burns, J. A., Schaffer, L. E. Greenberg, R. J. & Showalter, M. R. Nature 316, 115−119 (1985). | Article | ISI |
14.	Northrop, T. G. & Hill, J. R. J. geophys. Res. 88, 1−11 (1983).
15.	Morfill, G. E., Grim, E. & Johnson, T. V. Planet. Space Sci. 28, 1087−1100 (1980). | Article |
16.	Grün, E., Morfill, G. E. & Mendis, D. A. in Planetary Rings (eds Greenberg, R. & Brahic, A.) 275−332 (Univ. of Arizona Press, Tucson, 1984).
17.	Northrop, T. G., Mendis, D. A. & Schaffer, L. Icarus (in the press).
18.	Morfill, G. E., Grüin, E. & Johnson, T. V. J. geophys. Res. 88, 5573−5579 (1983). | ISI |
19.	Whipple, E. C. Rep. Prog. Phys. 44, 1197−1250 (1981).
20.	Hill, J. R. & Mendis, D. A. Moon and Planets 21, 3−15 (1979). | ISI |
21.	Schaffer, L. E. thesis, Cornell Univ., New York (1989).
22.	Burns, J. A. Am. J. Phys. 44, 944−949 (1976); Erratum 45, 1230 (1977).
23.	Burns, J. A., Lamy, P. L. & Soter, S. Icarus 40, 1−48 (1979). | Article | ISI |
24.	Burns, J. A., Cuzzi, J. N. & Showalter, M. R. Bull. Am. astr. Soc. 15, 1013−1014 (1983).