NEAT: ultra-precise differential astrometry to characterize planetary systems with Earth-mass exoplanets in the vicinity of our Sun

Abstract

The nearest solar-type stars are of prime interest for the science of exoplanets because they are the objects most suitable for direct detection and future spectroscopic investigations. Astrometry combined with radial velocity is the technique that can reveal planets with mass as small as the Earth mass in the 1 AU domain. We present in this contribution the result of a 3-year study on a mission capable to perform ultra-precise differential astrometry called NEAT (Nearby Earth Astrometric Telescope) and characterize planetary systems with Earth- mass exoplanets in the vicinity of our Sun. This mission requires exquisite calibration of the focal plane together with innovative approaches to obtain a very stable long focal telescope. This mission will be submitted in 2014 to the ESA M4 Call for Mission.