  We present the first scientific images obtained with a deformable secondary
mirror adaptive optics system. We utilized the 6.5m MMT AO system to produce
high-resolution (FWHM=0.07'') near infrared (1.6 um) images of the young (~1
Myr) Orion Trapezium theta 1 Ori cluster members. A combination of high spatial
resolution and high signal to noise allowed the positions of these stars to be
measured to within ~0.003'' accuracies. Including previous speckle data
(Weigelt et al. 1999), we analyze a six year baseline of high-resolution
observations of this cluster. Over this baseline we are sensitive to relative
proper motions of only ~0.002''/yr (4.2 km/s at 450 pc). At such sensitivities
we detect orbital motion in the very tight theta 1 Ori B2B3 (52 AU separation)
and theta 1 Ori A1A2 (94 AU separation) systems. Such motions are consistent
with those independently observed by Schertl et al. (2003) with speckle
interferometry, giving us confidence that these very small (~0.002''/yr)
orbital motions are real. All five members of the theta 1 Ori B system appear
likely gravitationally bound. The very lowest mass member of the theta 1 Ori B
system (B4) has K' ~11.66 and an estimated mass of ~0.2 Msun. There was very
little motion (4+/-15 km/s) detected of B4 w.r.t B1 or B2, hence B4 is possibly
part of the theta 1 Ori B group. We suspect that if this very low mass member
is physically associated it most likely is in an unstable (non-hierarchical)
orbital position and will soon be ejected from the group. The theta 1 Ori B
system appears to be a good example of a star formation ``mini-cluster'' which
may eject the lowest mass members of the cluster in the near future. This
``ejection'' process could play a major role in the formation of low mass stars
and brown dwarfs.
