| Astrophysics (Index) | About |
Epicyclic frequency in an accretion disk is the frequency at which fluid within the disk oscillates in a circular (or oval) motion relative to a normal orbital motion. The term is often used for such a radial oscillation (within the plane, radial epicyclic frequency) but is also used for oscillation out of the plane (vertical epicyclic frequency).
The term epicyclic frequency is similarly used in relation to the orbits of stars around a galaxy, which typically similarly oscillate relative to a circular orbital path.