Title: Formation flying for very high precision astrometry: NEAT and micro-NEAT mission concepts

Authors: Fabien Malbet; Alexis Brandeker; Alain Léger; Bjorn Jakobsson; Renaud Goullioud; Mike Shao; Antoine Crouzier

Addresses: Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), University of Grenoble-Alpes, CNRS, BP 53, F-3041 Grenoble Cedex 9, France ' Stockholm Observatory, AlbaNova University Center, SE-106 91 Stockholm, Sweden ' IAS, Université Paris XI, Bat. 121, F-91405 Orsay Cedex, France ' AOCS Department, OHB Sweden, Solna Strandväg 86, SE-17122 Solna, Sweden ' Jet Propulsion Laboratory, M/S 321-134, 4800 Oak Grove Drive, Pasadena, CA 91109, USA ' Jet Propulsion Laboratory, M/S 321-134, 4800 Oak Grove Drive, Pasadena, CA 91109, USA ' Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), University of Grenoble-Alpes, CNRS, BP 53, F-3041 Grenoble Cedex 9, France

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 study of telluric planets. In addition, the habitable zone is a region of special interest for astrobiology and for comparison with our own Earth. These two features point to astrometry as a unique tool for a systematic study of the architectures of planetary systems in that domain because the astrometric signal is larger the nearer the stars and the wider the planetary orbits whereas the other techniques favour smaller orbits. The astrometric technique is highly complementary and better suited for planets in the habitable zone (HZ). Recently, we have proposed two astrometric missions to ESA with different scales, but both of them use flying formation capability for the platform: Nearby Earth Astrometric Telescope (NEAT) as an M-class mission with a 1 m telescope and µNEAT as an S-class mission with a 0.3 m telescope. µNEAT can search and characterise giant planets, i.e., Neptune's mass and heavier, in the HZ around these stars, whereas NEAT can detect even smaller planets down to an Earth mass. The scientific impact of NEAT/µNEAT would be tremendous because they would provide the first exhaustive census of terrestrial/giant planet architecture in the HZ and beyond, around the nearest solar-type stars.

Keywords: astronomy; precision astrometry; exoplanets; calibration; formation flying; spacecraft formations; NEAT mission; micro-NEAT mission; planetary system architectures; astrometric signals; Nearby Earth Astrometric Telescope.

DOI: 10.1504/IJSPACESE.2014.060128

International Journal of Space Science and Engineering, 2014 Vol.2 No.1, pp.3 - 15

Available online: 27 Mar 2014 *

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