Accurate free and forced rotational motions of rigid Venus - Sorbonne Université
Article Dans Une Revue Astronomy & Astrophysics - A&A Année : 2010

Accurate free and forced rotational motions of rigid Venus

L Cottereau
  • Fonction : Auteur
  • PersonId : 1064969
J. Souchay
  • Fonction : Auteur
Safwan Aljbaae

Résumé

Context. The precise and accurate modelling of a terrestrial planet like Venus is an exciting and challenging topic, all the more interesting because it can be compared with that of Earth for which such a modelling has already been achieved at the milli-arcsecond level. Aims. We aim to complete a previous study, by determining the polhody at the milli-arcsecond level, i.e. the torque-free motion of the angular momentum axis of a rigid Venus in a body-fixed frame, as well as the nutation of its third axis of figure in space, which is fundamental from an observational point of view. Methods. We use the same theoretical framework as Kinoshita (1977, Celest. Mech., 15, 277) did to determine the precession-nutation motion of a rigid Earth. It is based on a representation of the rotation of a rigid Venus, with the help of Andoyer variables and a set of canonical equations in Hamiltonian formalism. Results. In a first part we computed the polhody, we showed that this motion is highly elliptical, with a very long period of 525 cy compared with 430 d for the Earth. This is due to the very small dynamical flattening of Venus in comparison with our planet. In a second part we precisely computed the Oppolzer terms, which allow us to represent the motion in space of the third Venus figure axis with respect to the Venus angular momentum axis under the influence of the solar gravitational torque. We determined the corresponding tables of the nutation coefficients of the third figure axis both in longitude and in obliquity due to the Sun, which are of the same order of amplitude as for the Earth. We showed that the nutation coefficients for the third figure axis are significantly different from those of the angular momentum axis on the contrary of the Earth. Our analytical results have been validated by a numerical integration, which revealed the indirect planetary effects.
Fichier principal
Vignette du fichier
01 Accurate free and forced rotational motions of rigid Venus.pdf (366.51 Ko) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-02480683 , version 1 (17-02-2020)

Identifiants

Citer

L Cottereau, J. Souchay, Safwan Aljbaae. Accurate free and forced rotational motions of rigid Venus. Astronomy & Astrophysics - A&A, 2010, 515, pp.A9. ⟨10.1051/0004-6361/200913785⟩. ⟨hal-02480683⟩
14 Consultations
96 Téléchargements

Altmetric

Partager

More