2007/10/31 by Matthew S. Tiscareno, Joseph A. Burns, Matthew M. Hedman +2 · 3 citations
Physics and Astronomy · #Astro and Planetary Science #Planetary Science and Exploration #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.1088/0004-6256/135/3/1083
published as Astron. J. 135, 1083-1091 (2008) · 31 pages, 10 figures; Accepted at AJ
arxiv created 2007/12/12 · openalex publication_date 2008/02/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present an extensive data set of ∼150 localized features from Cassini images of Saturn's A ring, a third of which are demonstrated to be persistent by their appearance in multiple images, and half of which are resolved well enough to reveal a characteristic "propeller" shape. We interpret these features as the signatures of small moonlets embedded within the ring, with diameters between 40 and 500 m. The lack of significant brightening at high phase angle indicates that they are likely composed primarily of macroscopic particles, rather than dust. With the exception of two features found exterior to the Encke Gap, these objects are concentrated entirely within three narrow (∼1000 km) bands in the mid-A ring that happen to be free from local disturbances from strong density waves. However, other nearby regions are similarly free of major disturbances but contain no propellers. It is unclear whether these bands are due to specific events in which a parent body or bodies broke up into the current moonlets, or whether a larger initial moonlet population has been sculpted into bands by other ring processes.