A New Model for the Formation of Terrestrial Planets and the Origin of Mars
Nader Haghighipour

The formation of the terrestrial planets of our solar system is one of the most outstanding problems of planetary astronomy. Traditional models of terrestrial planet formation have been successful to produce planets in the range of Venus and Earth. However, they have failed to produce Mars and Mercury analogs. Only when Jupiter and Saturn are assumed to have formed in their current positions and in highly eccentric orbits, do simulations succeed to produce planets with masses comparable to that of Mars. However, the intense interactions of these planets with the protoplanetary disk, combined with the short time of the formation of Mars, as suggested by cosmochemical data, point to a new approach to understanding the formation of the inner solar system. In this approach terrestrial planets are formed in a small and rather compact region of the protoplanetary disk and are scattered into their current orbits through interactions with one another and with planetary embryos. The appearance of such small-compact regions can be a natural consequence of the growth of solid objects in a circumstellar disk with a non-uniform surface density. I will present a new model of terrestrial planet formation capable of forming Mars based on this scenario, and will address the effects of giant planets on the evolution of the protoplanetary disk and the formation of the inner solar system. I will also show how this model can account for the water contents of terrestrial planets, the formation of the asteroid belt, and explain the formation of Mars as a stranded embryo within the first 10 Myr.