The Orion BN/KL complex is the nearest site of ongoing high-mass star
formation. Recent proper motion observations provide convincing evidence of a
recent (about 500 years ago) dynamical interaction between two massive young
stellar objects in the region resulting in high velocities: the BN object and
radio Source I. At the same time, Source I is surrounded by a nearly edge-on
disc with radius ~50 au. These two observations taken together are puzzling: a
dynamical encounter between multiple stars naturally yields the proper motions,
but the survival of a disc is challenging to explain. In this paper we take the
first steps to numerically explore the preferred dynamical scenario of Goddi et
al., in which Source I is a binary that underwent a scattering encounter with
BN, in order to determine if a pre-existing disc can survive this encounter in
some form. Treating only gravitational forces, we are able to thoroughly and
efficiently cover a large range of encounter parameters. We find that disc
material can indeed survive a three-body scattering event if 1) the encounter
is close, i.e. BN's closest approach to Source I is comparable to Source I's
semi-major axis; and 2) the interplay of the three stars is of a short
duration. Furthermore, we are able to constrain the initial conditions that can
broadly produce the orientation of the present-day system's disc relative to
its velocity vector. To first order we can thus confirm the plausibility of the
scattering scenario of Goddi et al., and we have significantly constrained the
parameters and narrowed the focus of future, more complex and expensive
attempts to computationally model the complicated BN/KL region.Comment: MNRAS in pres