The recent dynamical history of comet 67P/Churyumov-Gerasimenko

TL;DR

This study investigates the recent dynamical history of comet 67P/Churyumov-Gerasimenko, focusing on orbital evolution, perturbations from Jupiter, and chaotic behavior, using clone orbits and chaos indicators to understand its past trajectory.

Contribution

The paper provides a detailed analysis of the comet's orbital evolution and chaos, highlighting the impact of Jupiter encounters and non-gravitational forces on its recent history.

Findings

Jupiter's 1959 encounter significantly altered the orbit.

The comet's motion was chaotic before 1923.

Mean orbital trends were characterized over 275 and 10,000 years.

Abstract

This paper presents the past evolution of the orbital elements of comet 67P/Churyumov-Gerasimenko, target of the Rosetta spacecraft. The gravitational orbit of the comet is affected by the sublimation of ice from the nucleus that triggers non-gravitational forces. The comet also experienced several close encounters with Jupiter especially in 1959 and 1923 (less than 1 AU). These perturbations cause the chaoticity of the comet orbit at short time scale. The goal of this paper is to have a precise idea of the comet recent dynamical history. This is done in studying the mean trends of the comet orbital elements and also in characterizing its chaotic motion with the Fast Lyapunov indicator. To compute these mean trends, two sets (considering or not the non-gravitational forces) of 1000 clone orbits of the comet were considered. This paper shows that the last close encounter with Jupiter on February $4^{\text{th}}$, 1959 drastically modified the orbital elements of the comet (especially the perihelion distance from more than 2.7 AU prior the encounter to 1.3 AU after the encounter). The motion of the comet is also shown to be chaotic before the close encounter with Jupiter on October $2^{\text{nd}}$, 1923. The mean trends of the orbital elements of the comet are also presented in this paper (for two time scales : 275 years in the past and 10,000 years in the past).