Direct imaging of stars with radial velocity drifts.


G. Montagnier (1), X. Bonfils (2), D. Segransan (3), T. Forveille (2), S. Udry (3), J.-L. Beuzit (2) et al.


(1) ESO; (2) LAOG/CNRS, France; (3) Geneva Observatory, Switzerland


Radial velocity technique has been the most efficient method to detect exoplanets. It has permitted to give a comprehensive statistics of substellar companions up to 10 year periods. The analysis of radial velocity drifts is also a good way to make a selection of stars that host longer period companions which can then be detected and characterized by direct imaging technique. This type of selection has the advantage to only aim at stars with suspected substellar companions. However, radial velocity drift can only be identified on relatively old systems (typically older than 1 Gy) for which the contrast between the host star and its companion is not favorable for direct detection. If direct imaging of substellar objects around such old objects is not an easy task, the combination of imaging detection limits and radial velocity data - in case of non detection - allows to conclude on the nature of the companions. We will present the selection of the target and the analysis methods to characterize the companions. We will then discuss our results on the brown dwarf desert at large separation around solar-type stars. Next, we will show preliminary results of our program on M dwarfs, aiming at constraining the giant planet population around this type of object. We will finally conclude on the perspectives offered by this work to prepare the next generation high contrast imaging instruments.