Pr. Pierre Encrenaz President dujury

نویسندگان

  • Pierre Riaud
  • Pierre Encrenaz
چکیده

In this thesis work a complete study of the four quadrants coronagraph is presented This new coronagraph o ers performances of extremely large theorical rejection factor These performances open possibilities of exo planets detection around nearby stars The rst laboratory results gave an attenuation rate higher than on the central peak Thus I naturally studied all the possible uses of this coronagraph on ground based as well as on the space telescopes On the former this device can be used coupled with high order adaptive optics for detection of brown dwarves and hot giant planets around the closest stars On the latter I focalized my interest on the MIRI instrument Mid InfraRed Imager for the NGST telescope and on a space interferometer for Terrestrial Planet Finder of NASA Numerical simulations are presented within the framework of the Planet Finder ESO project Nevertheless an important problem must be solved the chromatism of phase shift Thus I will present three solutions leading to the achromatisation of the coronagraph R esum e Je pr esenterai dans ce travail de th ese une etude compl ete du coronographe a quatre quadrants propos e par D Rouan Ce nouveau coronographe o re des perfor mances de r ejection th eoriques extr emement importantes Ces performances ouvrent des possibilit ees de d etection d exo plan etes autour des etoiles proches Les premiers r esultats en laboratoire ont donn e des taux d att enuation sup erieurs a sur le pic central J ai donc naturellement etudi e toutes les utilisations possibles de ce coronographe au sol comme dans l es pace En premier lieu il peut etre utilis e sur les t elescopes au sol avec une optique adaptative a haut Strehl pour la d etection des naines brunes et des plan etes g eantes chaudes autour des etoiles les plus proches Ensuite je me suis int eress e a l utilisation du Q sur l instrument MIRI Mid InfraRed Imager du NGST puis sur un interf erom etre spatial pour Terrestrial Planet Finder de la NASA Des simulations num eriques seront pr esent ees dans le cadre du projet Planet Finder de l ESO N eanmoins un des probl emes majeurs du masque a quadrants reste le chromatisme du d ephasage de pour une utilisation en large bande dans le cadre du projet TPF Je pr esenterai donc des solutions permettant d achromatiser le coronographe

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تاریخ انتشار 2003