Box orbit

{{Short description|Type of gravitational orbit seen in triaxial systems}}

In stellar dynamics, a box orbit refers to a particular type of orbit that can be seen in triaxial systems, i.e. systems that do not possess a symmetry around any of its axes. They contrast with the loop orbits that are observed in spherically symmetric or axisymmetric systems.

In a box orbit, a star oscillates independently{{Citation needed|reason=In general, these oscillations are not independent, and the resulting figure is far from a rectengular parallelepiped, but the orbit is still called a box-orbit|date=March 2023}} 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.{{Citation

| last1 = Merritt

| first1 = D.

| author-link = David Merritt

| last2 = Valluri

| first2 = M.

| title = Resonant Orbits in Triaxial Galaxies

| journal = The Astronomical Journal

| volume = 118

| pages = 1177–1189

| date = September 1999

| issue = 3

|arxiv = astro-ph/9903452 |bibcode = 1999AJ....118.1177M |doi = 10.1086/301012 | s2cid = 14621588

}}

Such orbits are sometimes called "boxlets".

border="0" cellpadding="2" align="center" |+Examples of box orbits (in 2 dimensions)

Image:Box_orbit_begin.svg |Image:Box_orbit_full.svg |Image:Box_orbit_resonance.svg

align="center" |Beginning of a box orbit | align="center" |Many cycles of a box orbit | align="center" |A closed box orbit