  We investigate the effect of a planet on an eccentric orbit on a two
dimensional low mass gaseous disk. At a planet eccentricity above the planet's
Hill radius divided by its semi-major axis, we find that the disk morphology
differs from that exhibited by a disk containing a planet in a circular orbit.
An eccentric gap is created with eccentricity that can exceed the planet's
eccentricity and precesses with respect to the planet's orbit. We find that a
more massive planet is required to open a gap when the planet is on an
eccentric orbit. We attribute this behavior to spiral density waves excited at
corotation resonances that increase the disk's eccentricity and exert a torque
opposite in sign to that exerted by the Lindblad resonances. The reduced torque
makes it more difficult for waves driven by the planet to overcome viscous
inflow in the disk. Spectral energy distributions of transitional disks may
reveal the presence of an eccentric planet if they are matched by an inner edge
comprising a range of temperatures set by the semi-major axis and eccentricity
of the hole.
