Title: The Role of Giant Planets in Terrestrial Planet Formation

Authors: Harold F. Levison & Craig Agnor

Status: In Astronomical Journal.

Abstract: We present the results of simulations of the late stages of terrestrial planet formation under the gravitational influence of 6 different outer giant planetary systems with a wide range of dynamical characteristics. Our goal is to determine the role that the giant planets play in determining the number, mass and orbital characteristics of the resulting terrestrial planets and their general potential for habitability. Each of the giant planet systems affects the embryos in its own unique way. However, we find that the most profound effects are secular in nature. We also discovered that dynamical excitation of the embryos by the giant planets in one region can be transferred into another on short timescales via what we call secular conduction. Despite large differences in the behaviors of our systems, we have found general trends that seem to apply. The number, mass, and the location of the terrestrial planets are directly related to the amount of dynamical excitation experienced by the planetary embryos near 1AU. In general, if the embryos' eccentricities are large each is crossing the orbits of a larger fraction of its cohorts, which leads to a fewer number of more massive planets. In addition, embryos tend to collide with objects near their periastron. Thus, in systems where the embryos' eccentricities are large, planets tend to form close to the central star.

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