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Distribution of Kolmogorov-Sinaï Entropy in Self-Consistent Models of Barred Galaxies

Published online by Cambridge University Press:  12 April 2016

H. Wozniak  and
D. Pfenniger
H. Wozniak
Affiliation:
IGRAP/Observatoire de Marseille, F-13248 Marseille cedex 4, FranceE-mail:wozniak@observatoire.cnrs-mrs.fr
D. Pfenniger
Affiliation:
Observatoire de Genève, CH-1290 Sauverny, SwitzerlandE-mail:Daniel.Pfenniger@obs.unige.ch

Abstract

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The properties of chaos in 2D self-consistent models of barred galaxies are investigated using Kolmogorov-Sinai entropy hKS. These models are constructed with Schwarzschild’s method which combines orbits as elementary building blocks.

Most models are dominated by chaos near the 2/3 of the length of the bar and close to corotation. These locations correspond to regions where star-forming HII regions are observed because gas clouds could shock, shrink and fragment such that star formation could be ignited.

The model the most similar to N-body models shows a peak of hKS between the corners of the rectangular-like x1 orbits and the maximum extension points of the Lagrangian orbits. This emphasizes the role of Lagrangian orbits in the morphology of bars. Most models essentially contain ‘semi-chaotic’ orbits confined inside the corotation.

Type
Stellar Systems
Information
International Astronomical Union Colloquium , Volume 172: Impact of Modern Dynamics in Astronomy , 1999 , pp. 149 - 158
Copyright
Copyright © Kluwer 1999

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