Ground-based direct imaging of extra-solar planets supported by AO

Abstract

The detection of extra-solar planets made by direct imaging is an extremely challenging goal for astronomers due to the possibility to access the physical properties of planets and not only their existence. Using 8 m class telescopes joint with dedicated techniques (such as Simultaneous Differential Imaging aiming to suppress the speckle noise) it is possible, at present, to attain detection limit of 9–11 mag at 0.5 arcsec i.e. to access 3–10 M planets orbiting around young (100–200 Myr) nearby and late type stars. Searches for extra-solar planets carried out with the present technology are quite fundamental and critical not only for discovery of planets but also because it permits us to put constraints on theories of planets formation and migration. Besides, our understandings of the performances of sophisticated techniques such as the SDI is fundamental to plan new observational strategies, new generation instruments and telescopes. Speckles noise is, indeed, the main source of noise for observations in the NIR and visible and our ability in suppressing it is not so easily scaled at different parameters space. In this contribution I will present the main results that we obtained in on-going searches for planets carried out with NACO and NACO/SDI in the last years. A particular attention will be dedicated in comparing different observational strategies and in the employment of image processing techniques for recognizing, in an automatic way, planet features in deep images obtained with ground-based telescopes and AO facilities.