Evaluating GAIA performances on eclipsing binaries - I. Orbits and stellarparameters for V505 Persei, V570 Persei and OO Pegasi

The orbits and physical parameters of three detached, double-lined A-F ecli psing binaries have been derived combining H-P, V-T, B-T photometry from th e Hipparcos/Tycho mission with 8500-8750 Angstrom ground-based spectroscopy , mimicking the photometric+spectroscopic observations that should be obtai ned by GAIA, the approved Cornerstone 6 mission by ESA. This study has two main objectives, namely (a) to derive reasonable orbits for a number of new eclipsing binaries and (b) to evaluate the expected performances by GAIA o n eclipsing binaries and the accuracy achievable on the determination of fu ndamental stellar parameters like masses and radii. It is shown that a 1% p recision in the basic stellar parameters can be achieved by GAIA on well ob served detached eclipsing binaries provided that the spectroscopic observat ions are performed at high enough resolution. Other types of eclipsing bina ries (including semi-detached and contact types) and different spectral typ es will be investigated in subseguent papers in this series.