Origin of vestoids suggested from the space weathering trend in the visible reflectance spectra of HED meteorites and lunar soils

The extended visible reflectance spectra of asteroid 4 Vesta and Vestoids (R. BINZEL and S. Xu, Science, 260,186,1993) have been compared with the space weathering trend of HED meteorites and lunar soils. In accordance to our previous study (T. HIROI et al., Icarus, 115,374,1995), many Vestoids show more weathered visible reflectance spectra than those of Vesta and HED meteorites. The Vestoids outside the HED-lunar space weathering trend tend to have orbits which require large ejection velocities if they came from Vesta. This result suggests that the Vestoids off the HED-lunar space weathering trend are quite distinct from the other Vestoids and may come from other asteroid(s), such as the projectile which collided with Vesta and excavated the majority of Vestoids inside the Vesta family