Activated asteroids, missing family members, and pieces of planets

Small bodies in the solar system like asteroids and comets are getting a lot of attention from astronomers and NASA these days. Often disregarded as ‘rocks in space,’ small bodies can be some of the most geologically active bodies in the solar system from surface mass-shedding events to catastrophic disruptions leading to satellite formation. During my PhD, I pieced together the theory and evidence that ties many different small body morphologies (spin state, shape, multiplicity, etc.) into a coherent evolutionary model. Furthermore, small body populations are an archaeological record of Solar System history. Information is stored in the characteristics (composition, size, etc.) of individual bodies and the properties of the various populations as a whole. I present evidence that the asteroid sub-population with differentiated, achondritic compositions is likely from giant debris-creating impacts on the growing terrestrial planets and not from small, differentiated planetesimals. Specifically, I show that the Eureka family of Mars Trojans is likely a piece of plutonic rock from Mars. These results have strong consequences for the upcoming mission to Psyche.