Paul F. Wren

Date of Award

January 2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Space Studies

First Advisor

Ronald Fevig

Abstract

Binary asteroids have been observed among the Near Earth Asteroids, among the Main Belt Asteroids, and even in the Trans-Neptunian Object population. Many were discovered by light curve analysis, some by direct or radar imaging, and a few by stellar occultation. Some were discovered using ground-based telescopes, and others by space-based assets such as the Hubble Space Telescope. As good as these instruments may be, no confirmed binary asteroids in the Main Belt have a primary body less than one kilometer in diameter.

The primary goal of this research was to confirm the existence of Main Belt binary asteroid systems with components smaller than one kilometer in diameter. Another goal of this research was to estimate a lower bound for the percentage of all Main Belt asteroids less than one kilometer in diameter that are binary systems. Doublet craters are believed to be caused by binary asteroid impacts, and their numbers can serve as a proxy for the number of binary asteroids among all impactors. Doublet craters were studied on the surface of Ceres using the latest detailed imagery returned by NASA’s Dawn spacecraft. A large sample area on the surface of Ceres was systematically surveyed to identify and locate all impact craters greater than a minimum diameter. All possible pairings were examined and evaluated for their potential as doublets, and the likely doublets allowed the percentage of impact events in the sample area that are created by binary asteroids to be determined. This percentage is proportional to the percentage of Main Belt asteroids that are themselves binary systems.

The sizes of impactors that created the observed impact craters were determined using a crater scaling law, providing conformation of small binary asteroid systems in the Main Belt.

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