A Keplerian Orbit (or Kepler Orbit) is an orbit that follows a perfect ellipse, parabola, or hyperbola. It is the orbit that would be taken by a point mass orbiting another point mass with no other mass near enough to affect them. Spheres where any shell has its mass distributed homogeneously (spherically symmetric) act like point masses and planets and stars approximate this condition. Orbits diverge from Keplerian due to additional mass, e.g., other planets, near enough to affect the orbits, and divergence from the even distribution of mass described above, such as if one region near the surface was especially massive. Referenced by: Celestial Mechanics Corotation Torque Keplerian Disk Rotation Curve |