Detection and caractérisation of nearby planetary systems by astrometry - The NEAT mission proposed to ESA

Séminaire IPAG de Fabien Malbet (IPAG), jeudi 1er septembre 2011 à 11h00, IPAG seminar room

The scientific goal of the NEAT (Nearby Earth Astrometric telescope) mission is to detect and characterize planetary systems in an exhaustive manner down to 1 Earth Mass in the habitable zone and further away, around nearby solar-type stars. This survey would provide the actual planetary masses, the full characterization of the orbits for all the components of the planetary system down to that the Earth mass limit. Astrometry in space using small-angle differential astrometry between sources located up to 0.3◦ apart can reach a 0.05μas 1-σ accuracy that allows detecting dynamical effects due to even lower-mass orbiting planets on their central star. The NEAT mission can be accomplished with the use of a single mirror off-axis parabola telescope (D=1m) with a long focal length (f=40m) and an interferometric calibration of the position of 8 small movable CCDs located around a fixed central CCD by monitoring dynamical Young’s fringes originating from metrology fibers located on the primary mir- ror. The formation flying option has been studied as the reference mission in a scenario where the NEAT satellites are foreseen to operate at L2 for 5 years. NEAT science operations will devote 70% of the time to a survey of our closest F, G and K neighbors and the other 30% to pointed observations in predefined domains. NEAT is believed to be the only mission to date capable of discovering all Earth-mass planets in nearby planetary systems.