TITLE: 
 On the centre manifold of collinear points in the planar three body problem.

AUTHORS:
 Regina Martinez (reginamb@mat.uab.es) and Anna Sama (sama@mat.uab.es)
 Departament de Matematiques
 Universitat Autonoma de Barcelona,
 08193 Bellaterra, 
 Barcelona, Spain.

ABSTRACT:  
 We study the existence of invariant tori in a neighbourhood of the collinear
 equilibrium points of the planar three body problem. To this end some
 properties of the normal form of the Hamiltonian reduced to the 4D central
 manifold are proved. Using this normal form we show that the nondegeneracy
 conditions of KAM theorem are satisfied for all positive masses, including
 the 2:1 resonance case. The evaluation of the conditions is done numerically.