Direct Imaging Research of Exoplanet with Current Middle-sized Telescopes and Fututre Projects

Exoplanets search is one of the hottest topics in both modern astronomy and public domain. Over 1920 exoplanets have been confirmed mostly by the indirect radial velocity and transiting approaches, yielding several important physical information such as masses and radii. The study of the physics of planet formation and evolution will focus on giant planets through the direct imaging.    However, the direct imaging of exoplanets remains challenging, due to the large flux ratio difference and the nearby angular distance. In recent years, the extreme adaptive optics (Ex-AO) coronagraphic instrumentation has been proposed and developed on 8-meter class telescopes, which is optimized for the high-contrast imaging observation from ground, for the giant exoplanets. Gemini Planet Imager (GPI) has recently come to its first light, with a development period over 10 years. The contrast level has been pushed to 1E-6. Due to the space limitation or this or other reasons, none professional adaptive optics is available for most of current 3~4 meter class telescopes, which will limit its observation power to some extent, especially in the research of high-contrast imaging of exoplanets.    In this presentation, I will report the latest observation results by using our Portable AO (PAO) as a visiting instrument for high-contrast imaging on ESO’s 3.58-meter NTT telescope at LSO, and 3.5-meter ARC telescope at APO, respectively. It has demonstrated the PAO can be used for the scientific research of exoplanets and brown dwarfs. With an update of critical hardware, the dedicated instrument called as EDICT for imaging research of young giant exoplanets will be presented. And a preliminary design optimized for GSMT such as TMT will be also presented. Meanwhile, we have fully demonstrated in the lab a contrast on the order of 1E-9 in a large detection area, which is a critical technique for future Earth-like exoplanets imaging space missions. And a space program of JEEEDIS will also be presented in this talk.