An Ellipse's Semi-Major Axis (a) is half the distance between its furthest two points. The Semi-Minor Axis (b) is an analogous distance from the center to one of the nearest points on the ellipse. They are related: b = a (1 - e^{2})^{.5} Where e is the Eccentricity (e). The Semi-Major Axis is used in various orbital calculations. For example, for a non-circular (elliptical) orbit: T = 2π(a^{3}/μ)^{.5} Where:
Referenced by: Circumbinary Planet Moon Laplace Radius (r_{L}) |