FORMAÇÃO DE MERCÚRIO VIA COLISÕES EROSIVAS ENVOLVENDO CORPOS DE MASSAS SIMILARES

Abstract

The origin of Mercury still remains poorly understood compared to the other rocky planets of the Solar System. One of the most relevant constraints that any formation model has to fulfill refers to its internal structure, with a predominant iron core covered by a thin silicate layer. This led to the idea that it could be the product of a mantle stripping event by a giant impact. Previous studies in this line focused on binary collisions involving bodies of very different masses. However, such collisions are actually rare in N-body simulations of terrestrial planet formation, while collisions involving similar mass bodies appear to be more frequent. Here, we perform smooth particle hydrodynamics simulations to investigate the conditions under which collisions of similar mass bodies are able to form a Mercury-like planet. Our results show that such collisions can fulfill the necessary constraints in terms of mass (0.055 ME) and composition (30/70 silicate-to-iron mass ratio) within less than 5%, as long as the impact impact angles and velocities are properly adjusted according to well established scaling laws.