CONSERVATION OF THE TISSERAND PARAMETER AT CLOSE ENCOUNTERS OF INTERPLANETARY OBJECTS WITH JUPITER

This article has a long story. It was first written between 1979 and 1 981, at the beginning of our cooperation with Lubor Kresak. The goal o f the paper was to check the conservation of various formulations of t he Tisserand parameter and to investigate the relationships between th e T-values and the dynamical behaviours at close encounters with Jupit er. A first draft of the paper was subsequently enlarged and revised I n 1983, as new findings led us to the addition of another substantial section. Then, the paper has remained in a draft version up to now, be ing modified from time to time because of our committments with the co mputations of longterm evolutions of short-period comets. We want to h onour the memory of Lubor letting this article finally come out.