Constraining MOND Using the Vertical Motion of Stars in the Solar Neighborhood

Stars with a different vertical motion relative to the galactic disk have a different average acceleration. According to Modified Newtonian Dynamics (MOND) theories they should therefore have a different average orbital velocity while revolving around the Milky Way. We show that this property can be used to constrain MOND theories by studying stars in the local neighborhood. With the {\sc Hipparcos} dataset we can only place marginal constraints. However, the forthcoming {\sc GAIA} catalogue with its significantly fainter cutoff should allow placing a stringent constraint.