Where Exactly Are the Arcs of Neptune?

✍ Scribed by Mihaly Horanyi; Carolyn C. Porco

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 428 KB
• Volume: 106
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.1993.1190

✦ Synopsis

We show that periodic close encounters between Neptune's arc particles and the nearby satellite Galatea lead to a usually neglected secular perturbation on the osculating longitude at epoch ( (\varepsilon) ). This perturbation changes the effective mean motion (i.e., the mean motion averaged over a synodic period or longer). The correction is (0.0041^{\circ} /) day, which displaces the arcs (0.2 \mathrm{~km}) farther away from Galatea than was previously calculated by C. C. Porco (1991, Science 253,995 ), and also modifies the location of the arc-confining resonances by an equivalent amount. We examine this perturbation both analytically and numerically and demonstrate that the confinement mechanism based on single-satellite shepherding by Galatea (C. C. Porco, 1991, Science 253, 995) remains operational at the new position. 1993 Academic Press, Inc.