Détection et Caractérisation des Exoplanètes par Imagerie Directe avec IRDIS

Abstract : Since the first detection of an exoplanet orbiting a main sequence star in 1995, only a handful of planets have been detected by direct imaging because of the large contrast difference between stars and planets. SPHERE is a second generation instrument for the VLT dedicated to the detection of giant gaseous planets by direct imaging which will combine a dedicated extreme adaptive optics system and high-efficiency coronagraphs to ally high angular resolution and high contrast. One of its scientific modules, IRDIS, will offer several observing modes for exoplanet detection and characterization in the near infrared. During my thesis, I studied with detailed numerical simulations the performances of the dual-band imaging (DBI) and long slit spectroscopy (LSS) modes. In DBI I used SDI and ADI data analysis methods to attenuate the speckle noise and estimate the detection limits and photometric accuracy of IRDIS. Using this empirical accuracy I derived a best sequence of filter pairs for planet characterization and I estimated the lowest effective temperatures of the planets that could be characterized with IRDIS. In LSS, I developed a specific data analysis method for speckle dominated spectra and I studied its performances in details for exoplanet characterization. Finally, I worked on the characterization strategy for IRDIS with blind tests in DBI and LSS mode. These tests confirmed the results from the dedicated analysis of the two modes, and allowed me to study the discrimination of stellar contaminants in IRDIS data.
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Submitted on : Monday, March 1, 2010 - 4:00:29 PM
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Arthur Vigan. Détection et Caractérisation des Exoplanètes par Imagerie Directe avec IRDIS. Astrophysique [astro-ph]. Université de Provence - Aix-Marseille I, 2009. Français. ⟨tel-00460567⟩



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