Paper: astro-ph/0507180
Date: Thu, 7 Jul 2005 19:45:09 GMT (518kb)

Title: Oligarchic and giant impact growth of terrestrial planets in the
presence of gas giant planet migration

Authors: Martyn J. Fogg and Richard P. Nelson (Queen Mary, University of
London)

Comments: 17 pages, 11 figures, to be published in A&A. Higher resolution pdf
available at: http://www.users.globalnet.co.uk/~mfogg/3453fogg.pdf
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We present the results of N--body simulations which examine the effect that
gas giant planet migration has on the formation of terrestrial planets. The
models incorporate a 0.5 Jupiter mass planet undergoing type II migration
through an inner protoplanet--planetesimal disk, with gas drag included. Each
model is initiated with the inner disk being at successively increased levels
of maturity, so that it is undergoing either oligarchic or giant impact style
growth as the gas giant migrates. In all cases, a large fraction of the disk
mass survives the passage of the giant, either by accreting into massive
terrestrial planets shepherded inward of the giant, or by being scattered into
external orbits. Shepherding is favored in younger disks where there is strong
dynamical friction from planetesimals and gas drag is more influential, whereas
scattering dominates in more mature disks where dissipation is weaker. In each
scenario, sufficient mass is scattered outward to provide for the eventual
accretion of a set of terrestrial planets in external orbits, including within
the system's habitable zone. An interesting result is the generation of
massive, short period, terrestrial planets from compacted material pushed ahead
of the giant. These planets are reminiscent of the short period Neptune mass
planets discovered recently, suggesting that such `hot Neptunes' could form
locally as a by-product of giant planet migration.

\\ ( http://arXiv.org/abs/astro-ph/0507180 , 518kb)