Scientific rationale
Orbits of visual binaries began to be computed at the middle of the XIXth century, and spectroscopic binaries and eclipsing binaries were discovered at the end of that century ; by the end of the XXth century, the first exoplanets and the first binary asteroids were found. Although at first sight there seems to be little connection between the problematics related to the binary stars, the exoplanets, and to the Solar System, the problem of orbit determination actually appears as a common concern among these very different communities.
Over time, many orbit determination methods have been - and are still being - developed, not simply due to the various kinds of data (astrometric, photometric, spectroscopic, Light-Travel Time, etc.) ; despite these efforts, only a small number of masses are available to this day. The advent of the astrometric (but also photometric and spectroscopic) Gaia survey will bring a considerable change as thousands of exoplanets and millions of astrometric binaries are expected to be discovered and the processing of the data consequently requires automated, hands-off methods. The scientific content, and the possible biases, will be statistical in nature, and the data will often be subsequently combined to complementary external data to improve the orbit elements and allow mass estimations. The main aim of the workshop will be to foster communication between different communities to take benefit from their different expertises and promote future collaborations, in particular to improve a better exploitation of the Gaia outcome.