Orbits

right|thumb|Variation of orbital eccentricity    

scientific laws describing motion of planets around the Sun

minimum speed needed for an object to escape the gravitational influence of a primary body

time taken for a given object to make one complete orbit around another object, and applies in astronomy to mostly either planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars

lang=zxx|thumb|345px|The apsides refer to the farthest (2) and nearest (3) points reached by an orbiting planetary-mass object|planetary body (2 and 3) with respect to a primary, or host, body (1) An apsis ( (third declension); ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values.

angle between a reference plane and the plane of an orbit

parameter that determines the amount by which an orbit deviates from a perfect circle

situation in which an astronomical object's orbital period matches its rotational period

frame of reference not undergoing acceleration

orbit or rotation of an astronomical body opposite that of its primary body

speed at which it orbits around the barycenter of a system, usually around a more massive body. It can be used to refer to either the mean orbital speed, i.e. the average speed as it completes an orbit, or the speed at a particular point in its orbit

classical mechanics problem of three massive point particles interacting via Newtonian gravity; special case of the 𝑛‐body problem for 𝑛=3

one of the orbital elements used to specify the orbit of an object in space

component of the velocity in radial direction

parameters required to uniquely identify a specific orbit

one of the orbital elements used to specify the orbit of an object in space

to determine the motion of two point particles that interact only with each other

one of the orbital elements used to specify the orbit of an object in space

point where an orbit crosses a plane of reference to which it is inclined

orbit around the barycenter of the Sun

with regards to an astronomical body, the region in which it dominates the attraction of satellites

elliptical orbit used to transfer between two circular orbits of different altitudes, in the same plane

natural satellite following a distant, inclined, and often eccentric and retrograde orbit

orbit of an astronomical body equal to that body's average rotational period

Equation in orbital mechanics

vector used chiefly to describe the shape and orientation of the orbit of one astronomical body around another, such as a planet revolving around a star

geometrical plane in which an orbit lies

aspect of a heavenly body in which it makes a right angle with the direction of the Sun

angular parameter of Keplerian orbits

problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally

cause of tidal locking

Kepler orbit with an eccentricity of less than 1

named after Félix Tisserand

angular parameter that defines the position of a body that is moving along an elliptic Kepler orbit.; one of three angular parameters ("anomalies") that define a position along an orbit, the other two being the true anomaly and the mean anomaly

theorem that, among central-force potentials with bound orbits, there are only 2 types of central-force scalar potentials such that all bound orbits are closed: inverse square and radial harmonic

precession (rotation) of the orbit of a celestial body

trajectory of any object around a central body with more than enough speed to escape the central object's gravitational pull

describes the motion of an orbiting body as an ellipse, parabola, or hyperbola

unbound Kepler orbit with the eccentricity equal to 1

product GM of the gravitational constant G and the mass M of the body

orbit with a fixed distance from the barycenter

temporary orbit used during the launch of a satellite or other space probe

measure in astronomy

term in geometry; longest and shortest semidiameters of an ellipse

astronomy file format

device that senses the direction to one or multiple stars

spacecraft component controlling orientation

process that leads to gradual decrease of the distance between two orbiting bodies

longitude (measured from the point of the vernal equinox) at which the periapsis (closest approach to the central body) would occur if the body's inclination were zero

direction of imaginary projection onto the remote celestial sphere of the line perpendicular to planet Earth's orbital plane and passing though the orbital center

reference plane about whose axis the instantaneous orbital plane of a satellite precesses

in celestial mechanics, a dimensionless vector with direction pointing from apoapsis to periapsis

time between earliest and latest observations of a Solar System body like an asteroid or comet

main physical body of a gravitationally bound, multi-object system

orbital plane that is tipped away from the equator

angular speed required for a body to complete one orbit, assuming constant speed in a circular orbit which completes in the same time as the variable speed, elliptical orbit of the actual body

parameter in the gravitational two-body problem

physical law that describes the motion of objects in a Keplerian orbit around a body

region of a large body's orbit that could cause a small body to collide with it

vector quantity in celestial mechanics