  A high-angular momentum giant impact with the Earth can produce a Moon with a
silicate isotopic composition nearly identical to that of Earth's mantle,
consistent with observations of terrestrial and lunar rocks. However, such an
event requires subsequent angular momentum removal for consistency with the
current Earth-Moon system. The early Moon may have been captured into the
evection resonance, occurring when the lunar perigee precession period equals
one year. It has been proposed that after a high-angular momentum giant impact,
evection removed the angular momentum excess from the Earth-Moon pair and
transferred it to Earth's orbit about the Sun. However, prior N-body
integrations suggest this result depends on the tidal model and chosen tidal
parameters. Here we examine the Moon's encounter with evection using a
complementary analytic description and the Mignard tidal model. While the Moon
is in resonance the lunar longitude of perigee librates, and if tidal evolution
excites the libration amplitude sufficiently, escape from resonance occurs. The
angular momentum drain produced by formal evection depends on how long the
resonance is maintained. We estimate that resonant escape occurs early, leading
to only a small reduction (~few to 10%) in the Earth-Moon system angular
momentum. Moon formation from a high-angular momentum impact would then require
other angular momentum removal mechanisms beyond standard libration in
evection, as have been suggested previously.
