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Astrophysical Studies of Extrasolar Planetary Systems Using Infrared Interferometric Techniques Olivier Absil

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Astrophysical Studies of Extrasolar Planetary Systems Using Infrared Interferometric Techniques Olivier Absil Astrophysical studies of extrasolar planetary systems using infrared interferometric techniques Olivier Absil To cite this version: Olivier Absil. Astrophysical studies of extrasolar planetary systems using infrared interferometric techniques. Astrophysics [astro-ph]. Université de Liège, 2006. English. tel-00124720 HAL Id: tel-00124720 https://tel.archives-ouvertes.fr/tel-00124720 Submitted on 15 Jan 2007 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Facult´edes Sciences D´epartement d’Astrophysique, G´eophysique et Oc´eanographie Astrophysical studies of extrasolar planetary systems using infrared interferometric techniques THESE` pr´esent´eepour l’obtention du diplˆomede Docteur en Sciences par Olivier Absil Soutenue publiquement le 17 mars 2006 devant le Jury compos´ede : Pr´esident: Pr. Jean-Pierre Swings Directeur de th`ese: Pr. Jean Surdej Examinateurs : Dr. Vincent Coude´ du Foresto Dr. Philippe Gondoin Pr. Jacques Henrard Pr. Claude Jamar Dr. Fabien Malbet Institut d’Astrophysique et de G´eophysique de Li`ege Mis en page avec la classe thloria. i Acknowledgments First and foremost, I want to express my deepest gratitude to my advisor, Professor Jean Surdej. I am forever indebted to him for striking my interest in interferometry back in my undergraduate student years; for introducing me to the world of scientific research and fostering so many international collaborations; for helping me put this work in perspective when I needed it most; and for guiding my steps, from the supervision of diploma thesis to the conclusion of my PhD studies. Thank you Jean, from the bottom of my heart! My utmost gratitude also goes to Dr Vincent Coudé du Foresto for introducing me to the practical aspects and applications of stellar interferometry. Vincent’s spirit is present throughout this work. I am grateful to him for having kindly hosted me in Meudon and granted me privileged access to the FLUOR instrument. I am indebted to Dr Philippe Gondoin for giving me the opportunity to work on the GENIE project from its very beginning. Since that time and throughout the past four years, Philippe has continually encouraged and advised me, while giving me free rein to work on my favourite topics. I am grateful to Professors Jean-Pierre Swings, Jacques Henrard, Claude Jamar and to Dr Fabien Malbet, members of my thesis committee, for accepting to read and evaluate my work. This work would not have been possible without the help of Roland den Hartog, my comrade in arms on the GENIE and Darwin projects, who has become much more than a colleague over the past four years. I thank him for his incomparable support in developing GENIEsim, for the inordinate amount of time he has spent answering my emails and for his valuable comments on this dissertation. My gratitude also goes to the entire Darwin-GENIE team, including Malcolm, Anders, Lisa, Luigi, Pierre and Christian at ESA, Rainer, Philippe and Florence at ESO, and Eric at Leiden Observatory. I would like to express my warmest thanks to the wonderful FLUOR team (past and present) at Observatoire de Paris-Meudon. I have particularly enjoyed the fruitful collaboration and discussions with Emmanuel, Antoine, Guy, Pierre K., Bertrand, Pascal, Julien and Aglaé, as well as with Jason and Steve on the NOAO side. Special thanks go to Professor Pierre Léna, for drawing my attention to GENIE and for arranging my stay in Paris. My gratitude also goes to the whole CHARA crew at Mount Wilson (Hal, Theo, Judit, Laszlo, Nils, Dave, PJ, . ), for allowing me to use their terrific Array. Thanks to all of you for so many enjoyable moments on the mountain top, meeting bears, snakes and black widows, eating pumpkin pies on Halloween with Jason (thanks for sharing the recipe!), taking pictures of deers, flowers (and mosquitoes) in the wild with Emmanuel, welding cables in the freezing outdoors with Guy, spending rainy nights playing ping-pong and listening to Aglaé play the piano, counting dust and pollen with PJ, and learning real-time data reduction with Antoine. My thanks also go to my colleagues at Grenoble Observatory for their hearty welcome and enthusi- asm. I am particularly grateful to Jean-Charles for his tireless advice and support on the study of debris disks, and to Mark for fruitful discussions on interferometry in Antarctica. Contributions to large international projects such as GENIE, Darwin, Pegase or ALADDIN in- evitably rely on the input of many people. Marc Barillot, Cyril Ruilier and Frédéric Cassaing have been three recurrent collaborators, with whom I have particularly enjoyed working. Thanks to them for sharing their great ideas and for so many fruitful discussions. I also take the opportunity to thank Marc Ollivier, Alain Léger, Fabien Malbet, Jean-Michel Le Duigou, Denis Mourard, and all the people involved. I would like to acknowledge all my colleagues and friends at Institut d’Astrophysique et de Géo- ii physique de Liège for making the past four years so enjoyable. Special thanks go to my roommates, Dimitri (aka Monsieur ZOG) and Pierre (aka Poulpy, supplier of chocolate bread and psychedelic mu- sic) for countless discussions on interferometry, coronagraphy, as well as many less serious topics. I also wish to thank Emilie and Denis, who are beautifully carrying this work forward, Denise for taking care of my travels and refunds, and the regulars of the “pops” for so many feasty afternoons, evenings and nights! Finally, I take a particular pleasure in thanking all members of my family, in particular my parents for their moral support (especially when I needed it most) and their inspiration, not only during my PhD studies, but also for a long time before. Special thanks also to André and P-A for their careful reading of this dissertation. Last, but far from least, my most tender thanks go to Muriel for her unconditional love and support, always, and in particular during the final stages of this work (when she became a LATEX expert in less than two days). This thesis is dedicated to her. This research was supported by a fellowship from the Belgian National Science Foundation (“Aspirant du F.N.R.S.”). During his stay at the Observatoire de Paris-Meudon, the author was supported by a European Community Marie Curie Fellowship. Contents Notations and acronyms 1 Introduction 3 Exoplanets galore! . 3 Direct imaging and the quest for life outside the solar system . 5 Debris disks: getting warmer... 7 Objectives and outline of this work . 9 I Study of debris disks with stellar interferometry 13 1 An overview of stellar interferometry 15 1.1 Principles of stellar interferometry . 15 1.1.1 Fringe contrast . 16 1.1.2 Phase measurements and image reconstruction . 17 1.1.3 Practical design of a stellar interferometer . 18 1.2 Current interferometric facilities . 19 1.2.1 Facilities from the 1980s and 90s . 19 1.2.2 A new generation of arrays . 21 1.3 Application of stellar interferometry to circumstellar disks . 23 1.3.1 The interferometric view of Herbig Ae/Be stars . 24 1.3.2 The interferometric view of T Tauri stars . 25 1.3.3 First attempts at detecting debris disks . 26 2 A study of debris disks with CHARA-FLUOR 27 2.1 Principle and goals of the study . 27 2.1.1 Strategy for near-infrared debris disk detection . 28 2.1.2 The FLUOR instrument at the CHARA Array . 30 2.2 A prototypical debris disk star: Vega . 33 2.2.1 The observations . 33 2.2.2 Article: Circumstellar material in the Vega inner system revealed by CHARA- FLUOR ..................................... 34 iv C 2.3 Ongoing work and future prospects . 45 2.3.1 Follow-up observations of Vega . 45 2.3.2 Our next target: ǫ Eridani . 45 2.3.3 Perspectives at the CHARA Array and the VLTI . 47 II Ground-based nulling interferometry: towards exozodiacal disks 51 3 An introduction to ground-based nulling interferometry 53 3.1 Principle of nulling interferometry . 54 3.1.1 Principle of a two-telescope (Bracewell) nulling interferometer . 54 3.1.2 Geometric and instrumental stellar leakage . 57 3.1.3 Spatial and modal filtering . 58 3.1.4 Disentanglement of the astrophysical sources . 59 3.2 Scientific and technological preparation of Darwin/TPF-I . 61 3.3 A first generation of ground-based nulling instruments . 61 3.3.1 BLINC at the MMT . 61 3.3.2 The Keck Interferometer Nuller (KIN) . 62 3.3.3 The Large Binocular Telescope Interferometer (LBTI) . 64 3.4 The European effort: GENIE . 65 3.4.1 The VLTI infrastructure . 65 3.4.2 Nulling configurations at VLTI . 67 3.4.3 Background subtraction techniques . 69 3.4.4 The need for a GENIE simulator . 73 4 Simulated performance of ground-based nulling interferometers 75 4.1 GENIEsim: the GENIE simulation software . 75 4.1.1 Principle and architecture of the simulator . 76 4.1.2 Real-time correction of atmospheric turbulence . 78 4.1.3 Modal filtering and the fluctuations of coupling efficiency . 81 4.2 A performance study of the GENIE instrument . 84 4.2.1 Article: Performance study of ground-based infrared Bracewell interfero- meters ..................................... 84 5 Selected scientific applications of the GENIE instrument 99 5.1 Characterisation of debris disks around Vega-type stars .
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