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Imagerie par synthèse d'ouverture optique, application aux étoiles chimiquement particulières

Abstract : The on-going revolution due to high angular resolution observations promises to unlock tightly-kept secrets of stellar astrophysics. Complementary polarization diagnostics at high angular resolution will open new opportunities by resolving local polarized features always averaged, and thus lost, in classical spectro-polarimetry. After describing the issue of chemically peculiar stars (Ap) observations, I develop a numerical tool with which I show how interferometric measurements improve the reconstruction of the abundance map and magnetic topology. Observations at GI2T validate this spectro-polarimetric mode on an interferometer. Nevertheless, a first attempt to obtain data on Ap stars failed due to technical and meteorological reasons.

Aperture synthesis imaging is the natural extension of this differential methods. Yet, its application to Ap stars requires simultaneously high (u,v) coverage, high spectral resolution and eventually polarisation analysis. In the context of a spectro-imaging interferometer with a large number of telescopes (VITRUV proposition for the VLTI), I confirm the interest of planar optics by mean of VLTI observations. I study different combination concepts and compare there performances. Finally, I start the study of instrumental polarisation and asses the specifications for a polarimetric mode at VLTI.
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https://tel.archives-ouvertes.fr/tel-00011472
Contributor : Jean-Baptiste Le Bouquin <>
Submitted on : Monday, February 6, 2006 - 11:28:35 AM
Last modification on : Friday, November 6, 2020 - 3:48:23 AM
Long-term archiving on: : Saturday, April 3, 2010 - 9:51:30 PM

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  • HAL Id : tel-00011472, version 1

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Citation

Jean-Baptiste Le Bouquin. Imagerie par synthèse d'ouverture optique, application aux étoiles chimiquement particulières. Astrophysique [astro-ph]. Université Joseph-Fourier - Grenoble I, 2005. Français. ⟨tel-00011472⟩

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