Effect of planet eccentricity on spiral structure driven by an external planet or bound star. The simulations E, F, and G are shown. They have planet eccentricities ﹩e=0.0,0.25,0.5﹩ (left to right) and aspect ratios ﹩h/ r=0.04﹩. The simulations are shown at times with the planet near periapse. The planet mass ratios ﹩q=5\times 10^{-3}﹩. The planet’s semimajor axis is at 1.2 times ﹩R_{\mathrm{max}\,}﹩, the disk outer edge. High‐eccentricity planets more effectively clear gas away from the planet. Consequently, the spiral density waves driven by higher eccentricity planets are more tightly wound.