Planet and Satellite Systems

Grant #: NNX13AD56A
Senior Scientist: Anthony Dobrovolskis

First year: 

Planets and satellites can share orbits with the same period and mean distance from their primary star or planet. There are now three known types of co-orbital companions: 

Trojans, horse-shoes, and quasi-satellites. Our recent research have revealed a new, fourth class of co-orbital companions. Therefore our first task will be to characterize this new class better, through both analytic theory and numerical simulations. We also plan to characterize possible undiscovered satellites in the Pluto system, which might pose a collision hazard to the New Horizons spacecraft, approaching its rendezvous with the Pluto system in July 2015. 

Second year: 

Debris from impacts on the satellites of Jupiter and Saturn can enter temporary orbits about their parent planets, eventually re-impacting the source moon, or another satellite in the same system. We have found that such ejecta exchange is particularly important between co-orbital satellites; our next task is to determine its effects on the sizes and shapes of such moons. A related task is to study the stability of three small moonlets orbiting between Saturn's major moons Mimas and Enceladus. 

Third year: 

Synchronous satellites orbit a planet with the same period at which it rotates. We propose to determine the properties of synchronous satellites of Mars and Venus, which could be of great interest to future spacecraft missions. Because of Venus' long rotation period, it is commonly asserted that synchronous satellites of Venus are impossible. However, our preliminary simulations show that certain quasi-satellites of Venus would remain nearly synchronous with its rotation. 

Our final tasks will be to characterize the orbital distribution of binary stars, and the patterns of insolation (sunlight) on planets of binary stars. Such patterns have profound implications for the climate and habitability of extrasolar planets.