  During planet formation, a gas giant will interact with smaller protoplanets
that stray within its sphere of gravitational influence. We investigate the
outcome of interactions between gas giants and terrestrial-sized protoplanets
with lunar-sized companions. An interaction between a giant planet and a
protoplanet binary may have one of several consequences, including the delivery
of volatiles to the inner system, the capture of retrograde moons by the giant
planet, and the ejection of one or both of the protoplanets. We show that an
interesting fraction of terrestrial-sized planets with lunar sized companions
will likely be ejected into interstellar space with the companion bound to the
planet. The companion provides an additional source of heating for the planet
from tidal dissipation of orbital and spin angular momentum. This heat flux
typically is larger than the current radiogenic heating of the Earth for up to
the first few hundred million years of evolution. In combination with an
atmosphere of sufficient thickness and composition, the heating can provide the
conditions necesary for liquid water to persist on the surface of the
terrestrial mass planet, making it a potential site for life. We also determine
the possibility for directly detecting such systems through all-sky infrared
surveys or microlensing surveys. Microlensing surveys in particular will
directly measure the frequency of this phenomenon.
