Critical Ergos Curves and Chaos at Corotation

  • Donald Lynden-BellEmail author
  • Jaideep M. Barot
Part of the Lecture Notes in Physics book series (LNP, volume 626)


The theory of adiabatic invariants is developed to cover the gyration of a star about a nearly equipotential orbit in a galaxy with a strong bar. The guiding centres for such orbits follow curves of constant Ergos. The energy and the gyration adiabatic invariant give two constants of the motion. Critical Ergos curves have a pair of X-type gravitational neutral points which provide switches between trajectories that have the star circulating forward or backward relative to the corotating frame of the bar and those that liberate back to remain on one side of the galaxy’s centre.

An attempt to discover the dynamical basis of the apparently random switching, that has been observed in computations of orbits with finite amplitudes of gyration, FAILS to find any such chaos at small gyration amplitudes, where Ergos curves give a good description of guiding centre motion.


Saddle Point Drift Velocity Adiabatic Invariant Drift Trajectory Random Switching 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 2003

Authors and Affiliations

  1. 1.Institute of AstronomyThe ObservatoriesCambridgeUK
  2. 2.Clare CollegeCambridgeUK
  3. 3.Physics DeptThe Queen’s UniversityBelfastUK
  4. 4.Westminster SchoolLondonUK

Personalised recommendations