lundi 28 janvier 2019, par Johan Mazoyer (Jet Propulsion Laboratory)
Jeudi 31 janvier 2019 à 16h00 , Lieu : Salle de confĂ©rence du bâtiment 17
More than 3000 exoplanets have been discovered to date, but only a few have been imaged directly. However, by allowing the observation of circumstellar disks and planets (sometimes simultaneously around the same star, as in the case of β-pictoris), this method is a fundamental tool for the understanding the process of planetary formation. In addition, direct access to the light of the detected objects allows spectroscopy, paving the way to the full chemical analysis of exoplanets’ atmosphere and disks grains. Several coronagraphic instruments are currently observing to images of young Jupiters and/or Kuiper like disks. These instruments use coronagraphs optimized for circular, often un-obstructed apertures. Indeed, the remaining aberrations created by the atmosphere or optics defaults is limiting the contrast at levels far above the ones created by apertures discontinuities (inter-segment gap or secondary mirror mounts). However, the next generation of ground and space based telescopes will have to address the problem of apertures discontinuities in coronagraphy, if we want to obtain images and spectra of earth sized planets or dust grains below the snow line. My talk is about the next steps to make these detections a reality. First, I will present my current research to improve the contrast level of coronagraphs using deformable mirrors. Then, I will also show my work in the field of the post processing of high contrast images, specifically in the field of circumstellar disks, with the GPI instrument.
