Eccentric orbit
= Eccentric orbit
An orbit with nonzero <orbital eccentricity>. A bound <Kepler orbit> with $0<e<1$ is a noncircular <ellipse>; $e=1$ and $e>1$ describe the parabolic and hyperbolic unbound cases. A <semi-major axis> fixed by <Kepler's third law> need not equal the time average of the orbital radius.