The rotation of Mimas

¹ FUNDP-University of NamurDepartment of Mathematics & NAmur Center for Complex SYStems (NAXYS), Rempart de la Vierge 8, 5000 Namur, Belgium
e-mail: benoit.noyelles@fundp.ac.be
² IMCCE, Paris Observatory, UPMC, Univ. Lille 1, CNRS UMR 8028, 77 avenue Denfert Rochereau, 75014 Paris, France
³ Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
⁴ Université Pierre et Marie Curie Paris 6, 4 place Jussieu, 75005 Paris, France

Received: 24 June 2011
Accepted: 27 September 2011

Abstract

Context. The Cassini mission in the Saturnian system is an outstanding opportunity to improve our knowledge of the satellites of Saturn. The data obtained thanks to this mission must be balanced with theoretical models.

Aims. This paper aims at modelling the rotation of Mimas with respect to its possible internal structure.

Methods. We first built different interior models, considering Mimas to be composed of two rigid layers with different porosity. Then we simulated the rotational behaviour of these models in a three-degree of freedom numerical code, considering the complete ephemerides of a Mimas whose rotation is disturbed by Saturn. We also estimated the deviation of its longitudinal orientation caused by tides.

Results. We expect a signature of the internal structure up to 0.53° in the longitudinal librations and an obliquity between 2 and 3 arcmin, the exact values depend on the interior.

Conclusions. The longitudinal librations should be detectable, but inverting them to arrive at clues on the internal structure of Mimas is challenging.