Orbital evolution of Comet 1995 O 1 Hale - BoppM

Results from a series of long-term numerical integrations of orbits centred on that of C/1995O1 (Hale-Bopp) are presented. Initially, 33 orbits taken from various sources were integrated in realistic models of the solar system for various timescales about the present in the range (?3; +2)Myr and analyzed to assess the probability of diierent dynamical outcomes, such as a sungrazing state or the number of orbits since it was captured from a long-period orbit in the Oort cloud. Further integrations were performed using an ensemble of 26 orbits more closely clustered about the present orbit of the comet, based on a more accurate method of orbit determination. We nd that the ensemble half-life for the comet to be captured or ejected is on the order of 0.5Myr in the backward integrations and 1.2Myr in the forward integrations, although a few members of our ensemble were captured during strong encounters with Jupiter within 10 revolutions. Comet Hale-Bopp has a probability p '0:15 of evolving to a sungrazing end-state, and although not a `new' comet (in the sense of being recently captured from the Oort cloud) may be considered dynamically young.