Exoplanet science with astrometry from ground and space

Johannes Sahlmann
European Space Astronomy Centre, Madrid

Extrasolar planets are commonly found around stars in the Galaxy but many questions concerning their formation and evolution remain open. Further progress relies on obtaining a comprehensive exoplanet census over a wide range of stellar types and planet parameters, which necessitates the combination of complementary observational techniques. Accurate measurements of stellar positions, i.e. astrometry, can inform us on the properties of extrasolar planets that are difficult to obtain with other techniques. However, detecting the orbital reflex motion of the host star with a typical amplitude smaller than 0.1 milli-arcseconds is challenging 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, and highlight their contributions to the exoplanet field so far. In particular, I will show new results from an ongoing astrometric planet search around very low-mass stars and brown dwarfs with the VLT. Finally, I will discuss the Gaia space astrometry mission and present my view of its impact on exoplanet research.

22 April 2015, 11:00

Centro de Astrofísica
Rua das Estrelas
4150-762 Porto