Are there moonlets near the Uranian alpha and beta rings?

TL;DR

This paper investigates the possibility of small moonlets near Uranus's alpha and beta rings, analyzing Voyager 2 data to infer their existence and potential role in ring confinement.

Contribution

It provides estimates of moonlet locations and sizes based on ring structures, suggesting their potential influence on ring dynamics.

Findings

Quasi-periodic optical depth variations observed

Estimated moonlets are 2-7 km in radius

Moonlets likely help confine the rings

Abstract

The Voyager 2 Radio Science Subsystem occultations of the Uranian alpha and beta rings exhibit quasi-periodic optical depth variations with radial wavelengths that vary with longitude. These patterns may be wakes from small moonlets orbiting exterior to these rings. Based on the observed structures in the rings, we estimate that the moonlets would need to be located about 100 km exterior to the rings' semimajor axes and be 2-7 km in radius. Such moonlets could help keep the rings confined. Due to their small radii and presumed low albedo, the expected brightness of these moonlets is on the order of the noise in Voyager 2 images.