The leading theory for the origin of the Moon is the giant impact hypothesis, in which the Moon was formed out of the debris left over from the collision of a Mars-sized body with the Earth. Soon after its formation, the orbit of the Moon may have been very different than it is today. We have simulated the phases of the Moon in a model for its form...
Published in The Astrophysical Journal Letters
Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on WM Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the ...
Multiple impact basins formed on the Moon about 3.8 Gyr ago in what is known as the lunar cataclysm or late heavy bombardment. Many workers currently interpret the lunar cataclysm as an impact spike primarily caused by main-belt asteroids destabilized by delayed planetary migration. We show that morphologically fresh (class 1) craters on the lunar ...
Published in Science
The origin of the Moon's nonnegligible orbital eccentricity of 0.053 has no theoretical explanation. Lunar laser ranging indicates that tides on Earth are currently increasing the Moon's eccentricity. However, ocean tides were likely much weaker during the first billion years, allowing lunar tides to damp any primordial lunar eccentricity very earl...
We present simulations of Triton's post-capture orbit that confirm the importance of Kozai-type oscillations in its orbital elements. In the context of the tidal orbital evolution model, these variations require average pericenter distances much higher than previously published, and the timescale for the tidal orbital evolution of Triton becomes lo...
Although analytical studies on the secular motion of the irregular satellites have been published recently, these theories have not yet been satisfactorily reconciled with the results of direct numerical integrations. These discrepancies occur because in secular theories the disturbing function is averaged over orbital motions, whereas instead one ...
Published in Icarus
Published in EPSC Abstracts
The Jupiter-Trojan asteroid population remains significantly unexplored despite its importance in constraining the early history of the Solar System. To date, only two multiple Jupiter-Trojan asteroid systems have been imaged directly using adaptive Optics (AO) Systems on 8-10m class telescopes: (617) Patroclus-Menoetius (in L5), a similarly-sized ...
