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The rings of Uranus: Results of the 10 April 1978 occultation

Nicholson, P. D. and Persson, S. E. and Matthews, K. and Goldreich, P. and Neugebauer, G. (1978) The rings of Uranus: Results of the 10 April 1978 occultation. Astronomical Journal, 83 (10). pp. 1240-1248. ISSN 0004-6256. doi:10.1086/112318.

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Observations of the 10 April 1978 stellar occultation by the rings of Uranus are presented. Nine rings were observed and their radii and widths are calculated. Rings η,y, and δ are found to be most likely circular and coplanar, in agreement with previous analyses; the remaining rings are either noncircular or slightly inclined. The width of the є ring is a linear function of its radius from the center of Uranus, projected onto the satellites' orbital plane; this suggests that it forms one continuous noncircular ring. The optical depth profile of the є ring has not changed significantly since March 1977. A model of this ring which fits all available observations adequately is that of a uniformly precessing Keplerian ellipse coplanar with the satellites' orbits. This model permits predictions of the radius and width of the є ring for future occultations. The precession rate is used to determine J_2 for Uranus, on the assumption that precession is caused solely by the planetary oblateness and not by satellite-ring interactions.

Item Type:Article
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Nicholson, P. D.0000-0003-2275-4463
Additional Information:© 1978 American Astronomical Society. Received 26 June 1978. The authors gratefully acknowledge the assistance of R. Zinn, M. Aaronson, M. Clark, A. Guerra, F. Peralta, and L. Papic in making the Las Campanas observations, and of J. Elias in discussions on the desirability of using the 2.2-µm band. We also thank R. Lucinio and G. Forrester. PN and PG acknowledge many useful discussions with G. Colombo on the structure of the rings. We thank J. L. Elliot, R. L. Millis, and L. H. Wasserman for sending preprints of their unpublished results, This research was supported by NASA Grants NGL 05-002-140 and NGL 05-002-207 and NSF Grants AST 76-22676, AST 77-20516, and AST 76-24281.
Group:UNSPECIFIED, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
NASANGL 05-002-140
NASANGL 05-002-207
NSFAST 76-22676
NSFAST 77-20516
NSFAST 76-24281
Issue or Number:10
Record Number:CaltechAUTHORS:20130306-134542488
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Official Citation:The rings of Uranus - Results of the 10 April 1978 occultation Nicholson, P. D.; Persson, S. E.; Matthews, K.; Goldreich, P.; Neugebauer, G. Astronomical Journal, vol. 83, Oct. 1978, p. 1240-1248.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37350
Deposited By: Ruth Sustaita
Deposited On:06 Mar 2013 22:21
Last Modified:09 Nov 2021 23:28

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