Giant impacts and terrestrial planet formation

We perform more than 1,000 simulations of giant impacts for various parameter sets by using the SPH (smoothed particle hydrodynamic) method. Our main results are as follows: (1) 40% of giant impact events are not merging events. (2) Such imperfect accretion does not affect the final number and mass of the terrestrial planets, and formation timescale so much. (3) However, it leads to decrease of the final spin velocity, and (4) change of the core/mantle ratio. (5) The total mass of ejected material by giant impacts during standard terrestrial planet formation is statistically estimated to be about 10% of the total mass of terrestrial planets.