  In this paper, we present a study about the dynamical effects of the Galaxy
on the external region of the Oort Cloud. The aims of this paper are: i) to
determine an outer limit for the Oort Cloud; and ii) to analyse the dynamical
behaviour of the most external objects of the Cloud and how they are ejected
from the Solar System. This is undertaken by following the temporal evolution
of massless test particles in the Galactic environment of the solar
neighbourhood. Here we show that the effect of the perturbations from the
Galactic tide in the particles is similar to that find for the evolution of
wide binary stars population. Moreover, in the Oort Cloud we found a dynamical
structure around 10 5 au conformed by objects unbound of the Sun. This
structure allows us to define a transition region of stability and an outer
boundary for the Oort Cloud, and it is also in agreement with previous results
about the disruption of wide binary stars.
