For an object in an eccentric orbit orbiting a much larger body, the length of the orbit decreases with orbital eccentricity e, and is an ellipse. This can be used to obtain a more accurate estimate of the average orbital speed: The mean orbital speed decreases with eccentricity.

How does eccentricity affect an orbit?

Eccentricity is the deviation of a planet's orbit from circularity — the higher the eccentricity, the greater the elliptical orbit. An ellipse has two foci: the points inside the ellipse where the sum of the distances from both foci to a point on the ellipse is constant.

Does eccentricity affect orbital period?

For all ellipses with a given semi-major axis the orbital period is the same, regardless of eccentricity.