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Wm. R. Ward (Southwest Research Institute)
Although tidal dissipation is a plausible source of orbit circularization for some close companions, rho Cr B at 0.23 AU is too distant from its primary for this mechanism to be effective. An alternative mechanism that can operate when a planet orbits near a disk, is described. The planet excites a one-armed spiral apsidal wave in the vicinity of a secular resonance where the periastron precessions rates of planet and disk match. The resulting reaction torque on the planet can affect a rapid change in its eccentricity. The possible relevance of this to the orbits of extra-solar planets is discussed.