Radio Measurements of the stellar proper motions in the core of the
  Orion Nebula Cluster
  Using multi-epoch VLA observations, covering a time baseline of 29.1 years,
we have measured the proper motions of 88 young stars with compact radio
emission in the core of the Orion Nebula Cluster (ONC) and the neighboring
BN/KL region. Our work increases the number of young stars with measured proper
motion at radio frequencies by a factor of 2.5 and enables us to perform a
better statistical analysis of the kinematics of the region than was previously
possible. Most stars (79 out of 88) have proper motions consistent with a
Gaussian distribution centered on
$\overline{\mu_{\alpha}\cos{\delta}}=1.07\pm0.09\quad{\rm mas\,yr^{-1}}$, and
$\overline{\mu_{\delta}}=-0.84\pm0.16\quad{\rm mas\,yr^{-1}}$, with velocity
dispersions of $\sigma_{\alpha}=1.08\pm0.07\quad{\rm mas\,\,yr^{-1}},$
$\sigma_{\delta}=1.27\pm0.15\quad{\rm mas\,\,yr^{-1}}$. We looked for organized
movements of these stars but found no clear indication of radial
expansion/contraction or rotation. The remaining nine stars in our sample show
peculiar proper motions that differ from the mean proper motions of the ONC by
more than 3-$\sigma$. One of these stars, V 1326 Ori, could have been expelled
from the Orion Trapezium 7,000 years ago. Two could be related to the
multi-stellar disintegration in the BN/KL region, in addition to the previously
known sources BN, I and n. The others either have high uncertainties (so their
anomalous proper motions are not firmly established) or could be foreground
objects.
