Vesta’s Missing Moons: Comprehensive Search for Natural Satellites of Vesta by the Dawn Spacecraft

Lucy A. McFadden, David R. Skillman, Nargess Memarsadeghi, Jian-Yang Li, S.P. Joy, C.A. Polanskey, Marc D. Rayman, Mark V. Sykes, Pasquale Tricarico, Eric Palmer, David P. O’Brien, Stefano Mottola, Uri Carsenty, Max Mutchler, Brian McLean, Stefan E. Schröder, Nicolas Mastrodemos, Conrad Schiff, H. Uwe Keller, Andreas Nathues, Pablo Gutiérrez-Marques, et al.

In Press, available online 5 May 2015


Earth-bound searches for natural satellites of 4 Vesta have been reported since 1987. With use of technological advances and observing capability has come a reduction in the detectable size of a possible satellite. The Dawn mission brought a small camera close to Vesta itself. In our search, which was carried out with a comprehensive data acquisition strategy and by experienced searchers, we find no satellites to a detection limit as small as 3-meters radius. Various observation and analysis strategies are discussed in detail. It is now time to factor the null result of this search into the context of satellite formation among other main belt asteroids and to conduct dynamical modeling to explore the suspected forces contributing to the absence of satellites at Vesta today.