Argument of perihelion

Argument Of Perihelion
The orientation of an elliptical orbit can be specified by three orbital elements: the inclination, the ascending node and the argument of perihelion.

argument of perihelion
The angle between the ascending node and the perihelion of an orbit around the Sun, measured in the orbital plane and in the direction of orbital motion.

Argument of Perihelion
The angle (in the body's orbit plane) between the ascending node line and perihelion measured in the direction of the body's orbit. This angle is often denoted as lower-case omega (ω).

Argument of perihelion: Angle along the orbit of a planet or other solar system object as measured from the ascending node (analogous to right ascension and longitude).

An argument of perihelion of 0° means that the body will be at perihelion right when it crosses the ecliptic from South to North. An argument of perihelion of 90° means that the body will be at perihelion at its Northmost distance from the ecliptic.

Orbital elements describing the orientation of an orbit are orbital inclination (i), ascending node (Ω), and argument of perihelion (ω).

We now rotate the orbit about the z-axis by an angle known as the argument of perihelion, . (In more general treatments of rigid body motion, this would be called the angle .) ...

(T) [sometimes taken instead as an angular measure called "mean anomaly", M]; perihelion distance (q), usually given in AU; eccentricity (e) of the orbit; and three angles (for which the mean equinox must be specified) --- the argument of perihelion ...

See also: Orbital elements, Elements, Element, Node, Perihelion