Feet in orthogonal-Buekenhout–Metz unitals

Given an Orthogonal-Buekenhout-Metz unital $U_{\alpha,\beta}$, embedded in $PG(2,q^2)$, and a point $P\notin U_{\alpha,\beta}$, we study the set of feet, $\tau_{P}(U_{\alpha,\beta})$, of $P$ in $U_{\alpha,\beta}$. We characterize geometrically each of these sets as either $q+1$ collinear points or as $q+1$ points partitioned into two arcs. Other results about the geometry of these sets are also given.