Gaia: origin and evolution of the milky way

摘要

GAIA is the astrophysics candidate for the ESA Cornerstone 5 mission, which is to be selected in September 2000. The GAIA mission will provide unprecedented positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars in our Galaxy and throughout the Local Group. This amounts to about 1 per cent of the Galactic stelar population. Combined with astrophysical information for each star, provided by on-board multi-colour phtometry, these data will have the precision necessary to quantify the early formation, and subsequent dynamical, chemical and star formation evolution of the Milky Way Galaxy. Additional scientific products include detection and orbital classification of tens of thousands of extra-solar planetary systems, a comprehensive survey to objects ranging from huge numbers of minor bodies in our Solar System, through galaxies in the nearby Universe, to some 500 000 distant quasars. It will also provide a number of stringent new tests of general relativity and cosmology. A complete satellite design has been developed, including the proposed payload, corresponding accuracy assesments, and results form a prototype data reduction development. GAIA can be launched in 2009, within the specified budget for the next generation ESA Cornerstone missions.