1111.3019 (Benoît Noyelles)
Benoît Noyelles
This paper presents a study of the Poincar\'e-Hough model of rotation of the
synchronous natural satellites, in which these bodies are assumed to be
composed of a rigid mantle and a triaxial cavity filled with inviscid fluid of
constant uniform density and vorticity. In considering an Io-like body on a low
eccentricity orbit, we describe the different possible behaviors of the system,
depending on the size, polar flattening and shape of the core.
We use for that the numerical tool. We propagate numerically the Hamilton
equations of the systems, before expressing the resulting variables under a
quasi-periodic representation. This expression is obtained numerically by
frequency analysis. This allows us to characterize the equilibria of the
system, and to distinguish the causes of their time variations.
We show that, even without orbital eccentricity, the system can have complex
behaviors, in particular when the core is highly flattened. In such a case, the
polar motion is forced by several degrees and longitudinal librations appear.
This is due to splitting of the equilibrium position of the polar motion. We
also get a shift of the obliquity when the polar flattening of the core is
small.
View original:
http://arxiv.org/abs/1111.3019
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