The ANR, Agence Nationale de la Recherche, for supporting this project and the postdoctoral position of S. Khoperskov

To CNES, to the GEPI Laboratory of the Paris Observatory, to the Actions “Gaia” and “Structuration de l’Univers” of the Paris Observatory for  their financial support.

To all our collaborators, in particular Matthew Lehnert (IAP) and Françoise Combes (LERMA, Paris Observatory).

To Nicolas Leclerc, Stephane Thomas and Sabine Kimmel (GEPI, Paris Observatory), for their unique help.