We study the excitation of planet inclination by a novel secular-orbital resonance in multiplanet systems perturbed by binary companions which we call ivection. Ivection resonance happens when the nodal precession rate of the planet matches a multiple of the orbital frequency of the binary, and its physical nature is similar to the previously-studied evection resonance. Capture into an ivection resonance requires the nodal precession rate to slowly increase passed the resonant value during planet migration, and will excite the mutual inclination of the planets without affecting their eccentricities. If the system encounters another resonance (e.g., a mean-motion resonance) after being captured into an ivection resonance, resonance overlap can make the system dynamically unstable, ejecting the smaller planet. Using ivection resonance, we are able to explain why planets in Kepler-108 have significant mutual inclination but modest eccentricity. We also find a deficit of multiplanet systems which would have nodal precession period comparable to binary orbital period, suggesting that ivection resonance may inhibit the formation or destablize multiplanet systems with external binary companion.
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