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Caractérisation des exoplanètes par imagerie depuis le sol et l'espace : Application à la mission SPICES et à l'instrument VLT/NaCo

Abstract : Direct imaging is currently the only available method to characterize the atmosphere of long-period exoplanets (≥1 AU). This technique is difficult to carry out because it requires high contrasts at short angular separations (10^6-10^10 at ~0,2''). During my PhD thesis, I focused on two instruments : the SPICES mission and the VLT/NaCo instrument. SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a project of space coronagraph which aims to characterize in spectro-polarimetry cold exoplanets and faint circumstellar disks (≥1 zodi). I determined the science performance of the mission using numerical simulations. SPICES could characterize Jupiters at separations ≤5 AU and distances ≤10 pc, super-Earths at 1-2 AU for a few stars within 4-5 pc and possibly Earths around α Centauri A. Considering all stellar types, I estimated an amount of ~300 potential targets. In the second part of my PhD thesis, I analyzed images taken in coronagraphic and differential imaging modes of the NaCo instrument. The objective was to search for gas giant planets as cool as 500-1300 K at separations of 5-10 AU around a selected sample of young and nearby stars (<200 Myr, <25 pc). Median detection limits give contrasts of ~10−5 at 1'', corresponding to effective temperatures and masses of 1100 K and 10 MJ, and complement statistical studies based on radial velocities.
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https://tel.archives-ouvertes.fr/tel-00750252
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Submitted on : Wednesday, April 24, 2013 - 12:23:34 AM
Last modification on : Wednesday, November 17, 2021 - 12:28:46 PM
Long-term archiving on: : Monday, April 3, 2017 - 9:02:18 AM

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  • HAL Id : tel-00750252, version 2

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Anne-Lise Maire. Caractérisation des exoplanètes par imagerie depuis le sol et l'espace : Application à la mission SPICES et à l'instrument VLT/NaCo. Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]. Observatoire de Paris, 2012. Français. ⟨tel-00750252v2⟩

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