Chaotic motions of Prometheus and Pandora

被引：34

作者：

Goldreich, P ^{[1
]}

Rappaport, N

机构：

[1] CALTECH, Pasadena, CA 91125 USA

[2] Inst Adv Study, Princeton, NJ 08540 USA

[3] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

来源：

ICARUS | 2003年 / 162卷 / 02期

基金：

美国国家航空航天局; 美国国家科学基金会;

关键词：

satellites of Saturn; orbits; chaos;

D O I：

10.1016/S0019-1035(02)00080-5

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Recent HST images of the saturnian satellites Prometheus and Pandora show that their longitudes deviate from predictions of ephemerides based on Voyager images. Currently Prometheus is lagging and Pandora leading these predictions by somewhat more than 20degrees. We show that these discrepancies are fully accounted for by gravitational interactions between the two satellites. These peak every 24.8 days at conjunctions and excite chaotic perturbations. The Lyapunov exponent for the Prometheus-Pandora system is of order 0.3 year(-1) for satellite masses based on a nominal density of 0.63 g cm(-3). Interactions are strongest when the orbits come closest together. This happens at intervals of 6.2 years when their apses are antialigned. In this context, we note the sudden changes of opposite signs in the mean motions of Prometheus and Pandora at the end of 2000 occurred around the time their apsidal lines were antialigned. (C) 2003 Elsevier Science (USA). All rights reserved.

引用

页码：391 / 399

页数：9

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