The parameter A in [0.37, 0.404]

It seems that the homoclinic tangency is characterized by the red curve withouth the bubble. Hence, when one interpolates the logarithmic form of the red curve for A in [0.37, 0.474], one gets the homoclinic tangency curve; see the dotted black curve in Figure 3. At A = 0.45 the tangency happens roughly at b = 1. For A = 0.38 we have b in between 1.07 and 1.08.

*Figure 3: Same as Figure 2 with interpolation of the homoclinic tangency curve.*

The following movies show the manifolds for b = 1.07 and 1.08, with A = 0.38 and c = 0.1. Again, the circle of saddle type is shown in green, its stable manifold is blue, and its unstable manifold is red. Attractors are shown in yellow.

For b = 1.07 the unstable manifold accumulates on a chaotic attractor. The stable manifold forms the boundary of the basin of attraction. Note that the unstable manifold almost touches the stable manifold (310K).
For b = 1.08 the unstable manifold both accumulates on a chaotic attractor and intersects the stable manifold. The homoclinic tangency of the manifolds did not induce a boundary crisis (290K).

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	For b = 1.07 the unstable manifold accumulates on a chaotic attractor. The stable manifold forms the boundary of the basin of attraction. Note that the unstable manifold almost touches the stable manifold (310K).
	For b = 1.08 the unstable manifold both accumulates on a chaotic attractor and intersects the stable manifold. The homoclinic tangency of the manifolds did not induce a boundary crisis (290K).