  We investigate high-magnification events caused by wide binary stellar and
planetary systems under the moderately strong finite-source effect where the
diameter of the source star is comparable with the caustics induced by a binary
companion and a planet. From this investigation, we find that a characteristic
feature in the central perturbations induced by the binary systems commonly
appears in a constant range where the size of the caustic induced by the binary
companion is between 1.5 and 1.9 times of the diameter of the source, whereas
in the central perturbations induced by the planetary systems the feature
commonly appears in a range where the ratio of the size of the caustic induced
by the planet to the source diameter changes with the planet/primary mass
ratio. High-magnification events caused by the binary and planetary systems
with the characteristic feature produce a distinctive short-duration bump in
the residuals from the single-lensing light curve, where the bump occurs near
the time of peak magnification of the events. Because of a well-known
planet/binary degeneracy, we compare binary- and planetary-lensing events with
the short-duration bump in the residuals. As a result, we find the features of
the binary-lensing events that are discriminated from the planetary-lensing
events despite the moderately strong finite-source effect and thus can be used
to immediately distinguish between the binary and planetary companions. We also
find the feature that appears only in binary-lensing events with a very low
mass ratio or planetary-lensing events. This implies that the lens systems with
the feature have a very low mass binary companion (such as a brown dwarf) or a
planet.
