  We investigate the interaction between a giant planet and a viscous
circumstellar disk by means of high-resolution, two-dimensional hydrodynamical
simulations. We consider planet masses that range from 1 to 3 Jupiter masses
(Mjup) and initial orbital eccentricities that range from 0 to 0.4. We find
that a planet can cause eccentricity growth in a disk region adjacent to the
planet's orbit, even if the planet's orbit is circular. Disk-planet
interactions lead to growth in a planet's orbital eccentricity. The orbital
eccentricities of a 2 Mjup and a 3 Mjup planet increase from 0 to 0.11 within
about 3000 orbits. Over a similar time period, the orbital eccentricity of a 1
Mjup planet grows from 0 to 0.02. For a case of a 1 Mjup planet with an initial
eccentricity of 0.01, the orbital eccentricity grows to 0.09 over 4000 orbits.
Radial migration is directed inwards, but slows considerably as a planet's
orbit becomes eccentric. If a planet's orbital eccentricity becomes
sufficiently large, e > ~0.2, migration can reverse and so be directed
outwards. The accretion rate towards a planet depends on both the disk and the
planet orbital eccentricity and is pulsed over the orbital period. Planet mass
growth rates increase with planet orbital eccentricity. For e~0.2 the mass
growth rate of a planet increases by approximately 30% above the value for e=0.
For e > ~0.1, most of the accretion within the planet's Roche lobe occurs when
the planet is near the apocenter. Similar accretion modulation occurs for flow
at the inner disk boundary which represents accretion toward the star.
