### Keplerian orbit

**(Kepler orbit)**
(orbit following a perfect ellipse or other conic section)

A **Keplerian orbit** (or **Kepler orbit**) is an orbit
that follows a perfect **ellipse**, **parabola**, or **hyperbola**
(i.e., conic section).
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.

(*dynamics,orbits*)
http://en.wikipedia.org/wiki/Kepler_orbit

**Referenced by:**

celestial mechanics

corotation torque

epicycle

Keplerian disk

Kepler radius

rotation curve

index