Box orbit
Encyclopedia
In stellar dynamics
a box orbit refers to a particular type of orbit
which can be seen in triaxial systems, that is, systems which do not possess a symmetry
around any of its axes. They contrast with the loop orbits which are observed in spherically symmetric or axisymmetric systems.
In a box orbit, the star oscillates independently along the three different axes as it moves through the system. As a result of this motion, it fills in a (roughly) box-shaped region of space. Unlike loop orbits, the stars on box orbits can come arbitrarily close to the center of the system. As a special case, if the frequencies of oscillation
in different directions are commensurate
, the orbit will lie on a one- or two-dimensional manifold and can avoid the center. Such orbits are sometimes called "boxlets".
Stellar dynamics
Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. The long range of gravity and the slow "relaxation" of stellar systems prevent the use of the methods of statistical physics...
a box orbit refers to a particular type of orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
which can be seen in triaxial systems, that is, systems which do not possess a symmetry
Symmetry
Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection...
around any of its axes. They contrast with the loop orbits which are observed in spherically symmetric or axisymmetric systems.
In a box orbit, the star oscillates independently along the three different axes as it moves through the system. As a result of this motion, it fills in a (roughly) box-shaped region of space. Unlike loop orbits, the stars on box orbits can come arbitrarily close to the center of the system. As a special case, if the frequencies of oscillation
Oscillation
Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. Familiar examples include a swinging pendulum and AC power. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes...
in different directions are commensurate
Commensurability (mathematics)
In mathematics, two non-zero real numbers a and b are said to be commensurable if a/b is a rational number.-History of the concept:...
, the orbit will lie on a one- or two-dimensional manifold and can avoid the center. Such orbits are sometimes called "boxlets".
| Beginning of a box orbit | Many cycles of a box orbit | A closed box orbit |