In section 10: Planets and planetary systems
The impact crater at the origin of the Julia family detected with VLT/SPHERE?
It has been proposed that the ~140-km sized asteroid (89)Julia is the parent body of a small (33 members) and compact asteroid family that formed via a cratering collisional event. VLT/SPHERE observations presented by Vernazza et al. now permit a reconstruction of the 3D shape of this asteroid, and most noticeably reveal the presence of a large crater (D ~ 75 km) in the object's southern hemisphere. Based on numerical simulations, the authors further confirm the existence of the collisional family, and find that its properties are best explained by the impact of a D ∼ 8km asteroid on (89)Julia that occurred 30 to 120 Myrs ago, creating a D > 60 km impact crater at the surface. Thus, the crater directly imaged by VLT/SPHERE is likely to be the one at the origin of this family.