TITLE:
On Practical Stability Regions for the Motion of a Small Particle
close to the Equilateral Points of the Real Earth-Moon system

AUTHOR:
Angel Jorba
Departament de Matematica Aplicada i Analisi,
Universitat de Barcelona,
Gran Via 585, 08007 Barcelona, Spain
E-mail: angel@maia.ub.es

ABSTRACT:
This is a summary of a preliminary study on the existence of stability
regions near the equilateral libration points of the real Earth--Moon
system (here, by ``real'' Solar system we refer to the model defined
by the ephemeris DE406 from JPL). We start from a model that takes
into account the main effects coming from Earth, Moon and Sun to
locate regions where trajectories are confined for long time
intervals. Then, these regions are checked against a numerical
integration that takes into account the real motion of Earth, Sun and
the planets. This shows the existence of regions such that any initial
condition inside them produces a trajectory that remains there for at
least 1000 years.

This is the text of a talk delivered at the "III International
Symposium HAMSYS-98. Geometrical Methods in Hamiltonian Systems and
Celestial Mechanics" held in Patzcuaro (Mexico), December 7--11, 1998.