Impact Excavation on Asteroid 4 Vesta: Hubble Space Telescope Results

摘要: Hubble Space Telescope images of asteroid 4 Vesta obtained during the favorable 1996 apparition show an impact crater 460 kilometers in diameter near south pole. Color measurements within 13-kilometer-deep are consistent with excavation deep into a high-calcium pyroxene-rich crust or olivine upper mantle. About 1 percent was excavated by formation event, volume sufficient to account for family small Vesta-like asteroids that extends dynamical source regions meteorites. This may be site origin howardite, eucrite, and diogenite classes basaltic achondrite