Speaker
Dr
Vincent Robert
(IPSA & IMCCE - OBSPM)
Description
Accurate orbit determination require a large amount of observations dispatched over a large time span to allow for the best precision and extrapolation. This latter is of high importance in the context of future space missions.
In practice, most orbital models of the Solar System objects are fitted to data covering typically about one century. Even if the conditions are required for precise dynamical modeling, we emphasize an important caveat : ephemerides can sometimes be significantly biased while their extrapolation quickly diverges. Even though this could be due to various reasons, we found that an important one consists in the imprecision of past observations that are introduced in the adjustments. These observations were processed a long time ago with inaccurate star catalogs and with inaccurate methods compared to recent ones. No real efforts have been attempted to reanalyze these data a new time, considering the amount of time, mean and energy required.
Using photographic plates of planetary satellites, we demonstrate that a new reduction of old observations can improve significantly the ephemerides. In this framework and with support of the Gaia mission, the NAROO project has been initiated at Paris Observatory with the primary aim to reprocess the old astrometric observations with the best instrumental, algorithmic and numerical techniques. We discuss the impact of the project on future planetary and satellite ephemerides.
| Applicant type | First author |
|---|
Primary author
Dr
Vincent Robert
(IPSA & IMCCE - OBSPM)
Co-authors
Dr
Jean-Eudes Arlot
(IMCCE)
Dr
Valéry Lainey
(IMCCE)
Dr
William Thuillot
(Paris Observatory - IMCCE)
