[ { "id": "https://authors.library.caltech.edu/records/e6e7r-qmj79", "eprint_id": 37206, "eprint_status": "archive", "datestamp": "2023-08-19 09:30:50", "lastmod": "2023-10-23 17:14:03", "type": "monograph", "metadata_visibility": "show", "creators": { "items": [ { "id": "Goldreich-P-M", "name": { "family": "Goldreich", "given": "Peter" } }, { "id": "Rappaport-N", "name": { "family": "Rappaport", "given": "Nicole" } } ] }, "title": "Chaotic Motions of F-Ring Shepherds", "ispublished": "unpub", "full_text_status": "public", "keywords": "Satellites of Saturn, Orbits, Chaos", "note": "Submitted to Icarus on May 14, 2002\n\nWe thank R. French for providing us with a copy his preprint which contains the latest\nresults on the motions of Prometheus and Pandora, and for allowing us to reproduce from\nit the material in our Fig. 12. We are grateful to R. Jacobson for advice on initializing our\nintegrations in a manner compatible with the Voyager ephemerides. Research by PG was\nsupported by NSF grant AST-0098301 and that by NR by NASA Planetary Geology and\nGeophysics grant 344-30-53-02.\n\n
Submitted - 0205330v1.pdf
", "abstract": "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 20\u00b0. 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 0.35 yr^(-1) for satellite masses based on a nominal density of 1.3 gm/cm^(-3). Interactions are strongest when the orbits come closest together. This happens at intervals of 6.2 years when their apses are anti-aligned. In this context we note the sudden changes of opposite signs in the mean motions of Prometheus and Pandora at the end of 2000 occured shortly after their apsidal lines were anti-aligned.", "date": "2013-04-11", "date_type": "published", "id_number": "CaltechAUTHORS:20130228-111724121", "official_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130228-111724121", "rights": "No commercial reproduction, distribution, display or performance rights in this work are provided.", "funders": { "items": [ { "agency": "NSF", "grant_number": "AST-0098301" }, { "agency": "NASA Planetary Geology and Geophysics", "grant_number": "344-30-53-02" } ] }, "local_group": { "items": [ { "id": "Division-of-Geological-and-Planetary-Sciences" } ] }, "doi": "10.48550/arXiv.0205330", "primary_object": { "basename": "0205330v1.pdf", "url": "https://authors.library.caltech.edu/records/e6e7r-qmj79/files/0205330v1.pdf" }, "resource_type": "monograph", "pub_year": "2013", "author_list": "Goldreich, Peter and Rappaport, Nicole" } ]