Retrograde closed orbits in a rotating triaxial potential
Abstract
Four closed periodic orbit sequences are determined numerically, and their stability is investigated by the standard Floquet method, for the case of a specific, triaxial rotating potential. The sequences comprise (1) stable anomalous orbits that are tipped to the long axis which they circle, so that they also circle the short rotation axis, (2) unstable, anomalous orbits circling the intermediate axis, otherwise behaving like (1), (3) stable, normal retrograde orbits lying in the equatorial plane, which become unstable against perpendicular perturbations in Binney's instability strip, and (4) Zaxis orbits lying on the rotation axis, which, although stable in their inner section, become unstable to perturbations parallel to the intermediate axis farther out, and to the long axis farther out still. The entire set contains one composite sequence which is stable over the entire energy range, consisting of the outer section of the normal retrograde orbits, the sequence of the anomalous orbits, and the inner section of the Zaxis orbits. It is suggested that the composite sequence may be relevant to the dynamics of gas masses captured by rotating triaxial galaxies.
 Publication:

The Astrophysical Journal
 Pub Date:
 July 1982
 DOI:
 10.1086/160100
 Bibcode:
 1982ApJ...258..490H
 Keywords:

 Axes Of Rotation;
 Floquet Theorem;
 Galactic Rotation;
 Orbit Calculation;
 Orbit Perturbation;
 Galactic Structure;
 Gas Dynamics;
 Astrophysics