A pair of tangents SA and SB are drawn to parabola y2=8x from a foci S of ellipse x2a2+y2b2=1 (with a>b ),  such that ΔSAB is an equilateral triangle. If the tangents SA and SB pass through the extremities of minor axis of  ellipse, then 4e2 equals (where e is eccentricity of ellipse)