That's actually an interesting question because the keplerian elements are always changing or "osculating" under the effects of the gravity of the various planets, and this encounter will induce a very noticeable change in those elements. With the latest astrometric data we have a much better idea of what that change will be now than we did a year ago when we first found it. With the data we acquire during the encounter we will be able to further refine the orbit far into the future.