Exoplanet science with astrometry from ground and space

Séminaire IPAG de Johannes Sahlmann (ESA), jeudi 20 février 2014 à 11h00, IPAG seminar room

Measuring the positions of nearby stars can inform us on the presence and properties of extrasolar planets around them, because planets induce an orbital reflex motion on the host star. The typical amplitudes of this effect are in the range of 0.1 milli-arcseconds and smaller over timescales of years, which are challenging figures for present-day instruments. I will present an overview of the observing techniques that can reach the necessary precision, which include large ground-based facilities and dedicated space observatories. In particular, I will show results from an ongoing astrometric planet search around very low-mass stars using an 8-metre optical telescope on the ground. Finally, I will discuss the Gaia space astrometry mission and present my view of its impact on the field of exoplanet research.