The self-gravity model of longitudinal span of Neptune main arc Fraternite

TL;DR

This paper models the longitudinal span of Neptune's main arc Fraternite by incorporating self-gravity effects into the existing corotation resonance framework, explaining observed arc positions and material transport.

Contribution

It introduces a self-gravity component with distributed mass into the resonance model, enhancing understanding of arc structure and dynamics.

Findings

Model aligns arc positions with observations

Self-gravity influences arc's longitudinal span

Material transport among arcs is dynamically supported

Abstract

According to recent works [Tsui PSS \textbf{55}, 237-242 (2007), \textbf{55}, 2042-2044 (2007)], the Neptune Adams ring main arc Fraternite is regarded as captured by the corotation elliptic resonance (CER) potential of Galatea. The minor arcs Egalite(2,1), Liberte, and Courage are located at positions where the time averaged forces, due to the 42-43 corotation-Lindblad resonances under the central field of Neptune, vanish. With adequately chosen Fraternite mass and Galatea eccentricity, this model gives minor arc locations compatible to observed positions, and allows a dynamic transport of materials among arcs. To complement this model, the effect of self-gravity of Fraternite, with a distributed mass, is evaluated together with the CER potential to account for its $10^{0}$ longitudinal span. Although self-gravity is the collective action of all the particles in the arc, each individual particle will see the self-potential with a central maximum as an external potential generated by other particles.