TITLE:
THE QUASI-BICIRCULAR PROBLEM FOR THE EARTH-MOON-SUN PARAMETERS

Authors:
M.A. ANDREU, C. SIMO  
Dept. Matem\`{a}tica Aplicada i An\`{a}lisi,
Univ. Barcelona, Gran Via 585, 08007 Barcelona, Spain.
e-mails: mangel@maia.ub.es, carles@maia.ub.es

ABSTRACT:
The quasi-bicircular problem is a restricted four body problem
where three masses are revolving in a quasi-bicircular motion (that is,
a coherent motion close to circular), the fourth mass being small and
not influencing the motion of the three primaries. A quasi-bicircular
solution of the three body problem is computed for the Earth-Moon-Sun
parameters. Then, the Hamiltonian governing the motion of the fourth 
particle under the gravitational influence of the first three masses is 
derived. Some resonant periodic orbits around L1 and L2 are shown.
The system is reduced to an approximate center manifold and the periodic
orbit found are used to check the range of validity of the approximation.
