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Modelling the Diversity of Outer Planetary SystemsThe process of planetary growth is extremely complicated, involving a myriad of physical and chemical processes, many of which are poorly understood. The ultimate configuration that a planetary system attains depends upon the properties of the disk out of which it grew, of the star at the center of the disk and, at least in some cases, of the interstellar environment. In an effort to numerically survey the possible diversity of planetary systems, we have constructed synthetic systems of giant planets and integrated their orbits to determine the dynamical lifetimes and thus the viability of these systems. Our construction algorithm begins with 110 -- 180 planetesimals located between 4 and 40 AU from a one solar mass star; most initial planetesimals have masses several tenths that of Earth. We integrate the orbits of these bodies subject to mutual gravitational perturbations and -as drag for 10(exp 6) - 10(exp 7) years, merging any pair of planetesimals which pass within one-tenth of a Hill Sphere of one another and adding "gas" to embryos larger than 10 Earth masses. Use of such large planetesimal radii provided sufficient damping to prevent the system from excessive dynamical heating. Subsequently, systems were evolved without gas drag, either with the enlarged radii or with more realistic radii. Systems took from a few million years to greater than ten billion years to become stable (10(exp 9) years without mergers of ejections). Some of the systems produced with the enlarged radii closely resemble our outer Solar System. Many systems contained only Uranus-mass objects. Encounters in simulations using realistic radii resulted in ejections, typically leaving only a few planets per system, most of which were on very eccentric orbits. Some of the systems that we constructed were stable for at least a billion years despite undergoing macroscopic orbital changes on much shorter timescales.
Document ID
20020067730
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Lissauer, Jack J.
(NASA Ames Research Center Moffett Field, CA United States)
Levison, H. F.
(Southwest Research Inst. United States)
Duncan, M. J.
(Queens Univ. Kingston, Ontario Canada)
DeVincenzi, Donald L.
Date Acquired
August 20, 2013
Publication Date
January 1, 1998
Subject Category
Astrophysics
Meeting Information
Meeting: Division of Planetary Sciences of the American Astonomical Meeting
Location: Madison, WI
Country: United States
Start Date: October 11, 1998
End Date: October 16, 1998
Sponsors: American Astronautical Society
Funding Number(s)
PROJECT: RTOP 344-30-50-01
Distribution Limits
Public
Copyright
Other

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