This paper presents the past evolution of the orbital elements of the Rosetta target comet 67P/Churyumov-Gerasimenko (67P/C-G in the following text). The gravitational orbit of the comet is affected by the sublimation of ice from the nucleus that triggers a non-gravitational forces. The comet also experiences several close encounters with Jupiter especially in 1959 and 1928 (less than 1 AU). These perturbations cause the chaoticity of the comet at short term. The goal of this paper is to present when the chaoticity appears and the mean trends of the orbital elements in the past.
Mon, 8 Dec 14