  The large number of exoplanets found to orbit their host stars in very close
orbits have significantly advanced our understanding of the planetary formation
process. It is now widely accepted that such short-period planets cannot have
formed {\em in situ}, but rather must have migrated to their current orbits
from a formation location much farther from their host star. In the late stages
of planetary formation, once the gas in the proto-planetary disk has dissipated
and migration has halted, gas-giants orbiting in the inner disk regions will
excite planetesimals and planetary embryos, resulting in an increased rate of
orbital crossings and large impacts. We present the results of dynamical
simulations for planetesimal evolution in this later stage of planet formation.
We find that a mechanism is revealed by which the collision-merger of planetary
embryos can kick terrestrial planets directly into orbits extremely close to
their parent stars.
