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Contribution A Letude De Linterferometrie Annulante Pour La Detection Dexo Planetes
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Book Synopsis Contribution à l'étude de l'interférométrie annulante pour la détection d'exo-planètes by : Bruno Chazelas
Download or read book Contribution à l'étude de l'interférométrie annulante pour la détection d'exo-planètes written by Bruno Chazelas and published by . This book was released on 2007 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nulling interfermetry is an observation technique that will enable space missions like DARWIN (European Space Agency) or TPF-I (NASA) to detect and to spectrally characterize the atmospheres of terrestrial extra-solar planets and to find possible bio-signatures. This PhD is a theoretical and experimental study of this technique. After a presentation of the astrophysical context justifying the use of such instruments, this manuscript is focalized on the experimental difficulties to get the high levels of interferometric extinction required to detect planets and the way to stabilize such extinctions. An interferometric test bench : NULLTIMATE has been designed to characterize achromatic phase shifters, one of the central parts of a nulling interferometer. This laboratory test bench will be used in the spectral range of the future instrument 6 − 18 μm. It has been designed to work at cryogenic temperatures. It will be used to test four different phase shifters, with high extinction ratios (in the 10−5 range), and to measure their phase shift versus the wavelength. This bench will also enable to test extinction stabilization techniques.
Book Synopsis Interférométrie annulante pour l’exoplanétologie by : Sophie Jacquinod
Download or read book Interférométrie annulante pour l’exoplanétologie written by Sophie Jacquinod and published by . This book was released on 2010 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past 15 years, the field of exoplanets detection has considerably expanded. Detection methods, first indirect, have allowed to discover no less than 420 new “worlds”, sometimes astonishing. Scientists want now to characterize these exoplanets (particularly telluric ones) and Nulling interferometry is one of the direct detection methods assessed to do this. Within this framework, several space based projects are developed. Due to the complexity of these missions, it is necessary to test, first in laboratory, some technological aspects, as the principle of nulling interferometry. In 2006, CNES has decided to conduct an R&D on the payload of a two-telescope space based interferometer (typically the PEGASE instrument). Thus, the PERSEE test bench (Pegase Experiment for Research and Stabilization of Extreme Extinction) was conceived. The idea of PERSEE is to couple a nulling interferometer with a free flying simulator allowing introducing realistic disturbances and correcting them with active internal loops controlling the optical path difference and the pointing. This PhD work presents the design, the study and the development of one of the sub-systems of the bench: the beam combiner. This module is a new version of the Modified Mach-Zehnder beam combiner proposed by Serabyn et al. (2001). It has the particularity to combine the nuller and the Fringe Tracker system in order to minimize differential paths.
