  We have investigated effects of early stellar encounters on a protoplanetary
disk (planetesimal disk) and found that they can explain the high
eccentricities and inclinations observed in the outer part ($>42$AU) of the
Edgeworth-Kuiper Belt (EKB). The proto-sun is considered as a member of a
stellar aggregation that undergoes dissolution on a timescale $\sim 10^8$yrs,
such that a planetesimal disk experiences a flyby encounter at pericenter
distance ($q$) on the order of 100AU. We simulated dynamical evolution of a
planetesimal (test particle) disk perturbed by a passing star. We show that the
stellar encounter pumps the velocity dispersion in the disk in the outer parts
($> 0.25q$). Planet formation is forestalled in that region. We also find that
a stellar encounter with pericenter distance $q \sim 100-200$AU could have
pumped up the velocity dispersion of EKB objects outside 42AU to the observed
magnitude while preserving that inside Neptune's 3:2 mean-motion resonance
(located at 39.5AU), which allows for the efficient capture of objects by the
sweeping of the 3:2 resonance during orbital migration by proto-Neptune.
