Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 2K017

NEAT: an astrometric mission to detect and characterize nearby habitable planetary systems

Malbet, Fabien (IPAG, Grenoble, France)
Crouzier, Antoine (IPAG, Grenoble, France)
Goullioud, Renaud (JPL, Pasadena, USA)
Lagage, Pierre-Olivier (CEA/AIM, Saclay, France)
Léger, Alain (IAS, Orsay, France)
Shao, Mike (JPL, Pasadena, France)
NEAT consortium, (

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. Radial velocity and transit searches have been the most successful techniques so far to detect exoplanets and characterize them so far, but direct imaging and microlensing have also produced intriguing and interesting discoveries. In the last decade, we have learned that planetary systems are much more diverse than originally thought. Part of the reason is that the planet-detecting techniques used so far are biased towards finding ”exotic” planets: very close in or very far out, also because the middle ground is harder to detect. Astrometry is a unique tool for a systematic study of the architectures of planetary systems in that intermediate domain because the astrometric signal is larger the nearer the stars and the wider the planetary. Astrometry has not been used much so far because even Hipparcos, with its ground-breaking accuracy of 1mas, was not able to detect planets during its mission lifetime. The ESA corner stone mission Gaia will improve upon the accuracy of Hipparcos by two orders of magnitude, and is expected to find Jupiter-mass planets by the thousands. But Gaia was not optimized to find planets, and in particular will not be able to find planets around nearby solar-like stars, because the stars are so bright that they saturate Gaia’s detectors. Recently, we have proposed two astrometric missions to ESA at different scales: NEAT as an M-class mission with a 1m telescope and microNEAT as an S-class mission with a 0.3m telescope. MicroNEAT can search and characterize giant planets, i.e. Neptune’s mass and heavier, in the HZ around these stars, whereas NEAT can detect even smaller planets down to the Earth mass. NEAT/microNEAT would provide the first exhaustive census of terrestrial/giant planet architecture in the HZ and beyond, around the nearest FGK stars.

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