**Academic Letter **
__Tetsushi Ueta__, Hiroshi Kawakami, On Unstable Saddle-Node Connecting Orbit in a Planer Autonomous System, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol.E79-A, No.11, 1581-1586, Nov. 1996.
**Abstract: ** We found a novel connecting orbit in the averaged Duffing-Rayleigh equation. The orbit starts from an unstable manifold of a saddle type equilibrium point and reaches to a stable manifold of a node type equilibrium. Although the connecting orbit is structurally stable in terms of the conventional definition of structural stability, it is structually unstable since a one-dimensional manifold into which the connecting orbit flows is unstable. We can consider the orbit is one of global bifurcations governing the differentiability of the closed orbit.

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