Natural satellites dynamics and internal structure 23 September 2004 Valéry Lainey, MAGE network

Brief Presentation Teaching : 39 hours teaching in 2001 (Lille-University) DEA, PhD Thesis (Galilean satellites) Keywords: celestial mechanics, numerical simulations, ephemerides under contract with IMCCE/OV Keywords: OV and Solar system, external Jovian satellites 2003 Post-doc Keywords: observations, reduction, PHEMU Post-doc Keywords: Phobos, Deimos, Mars Express Paris Bruxelles Bangalore

New Dynamical Model of the Galilean Satellites (PhD thesis) Choice of a synthetic model (numerical tools and analytical representation)  Method in three steps: 1-High sensitive modelling (satellites oblateness, etc.) (Lainey, Duriez, Vienne 2001, Celes. Mech.) 2-Numerical integration of variational equations (fit to the observations) (Lainey, Duriez, Vienne 2004, A&A) 3-Digital filtering and frequency analysis  Improvement of an order of magnitude (internal precision) with respect to the former model (E5)

(Lainey, Arlot, Vienne 2004, A&A, in press)  L1 fit (external precision: few tens of km) 1’’≈3000 km Available at: New Dynamical Model of the Galilean Satellites (PhD thesis)

Observational part (post-doc) Albedo map (Galileo) Albedo and phase correction for the PHEMU97 campaign flux time (hours) (Vasundhara, Arlot, Lainey, Thuillot 2003, A&A) Mutual events (PHEMU)

Close flybys between MEX/Phobos (2005-?) (mass, J2, C22, …, centre of figure/centre of mass)  Great interaction between natural and artificial satellites dynamics fields  first direct determination of the dynamical oblateness of Phobos! MaRS: Mars Radio Science Experiment

I’m here…! ROB Arrival on April 1 st … (on a sunny day!)  PC on Linux and Windows facilities  Sharing the office with M.Beuthe (Mars topography, MEX…) Royal Observatory of Belgium (ROB)

ROB TEAM and interactions A lot of interesting discussions in a quite friendly environment: O.Karatekin (MOLA and Phobos) N.Rambaux (rotation of Solar system bodies, …) A.Rivoldini (computer stuff, swimming pool…) P.Rosenblatt: working on the dynamics of artificial satellites  GREAT interaction natural/artificial satellites (same methods!)  Result = GINS + NOE “We speak the same language”

MAGE post-docs and interactions I’ve already met: O.Verhoeven at ROB  possible interaction on Martian dissipation (Phobos secular acceleration) S.Pireaux at a summer school related to relativistic effects  Possible interactions on artificial satellites dynamics

MaRS team  Introduced to MaRS team since April!  Already assisted to several meeting  Gave a talk on July 7 th 2004

Conclusion  The best is about to come with MEX flybys