# Les systemes binaires jeunes et leur environnement proche: observations a haute resolution angulaire

Abstract : The work presented in this thesis focuses on some properties of pre-main sequence binary systems: their proportion among various populations, the frenquency and properties of dust and gaz discs in these systems, and the interaction of these discs with the two stellar components of the system. Several high-angular resolution imaging techniques are used to serve these purposes, as well as Monte-Carlo simulations. The binary frequency is determined in two two-million years-old stellar clusters. Then, a self-consistent comparison of these results with previously published surveys is performed. These data are compared to the predictions of formation and dynamical evolution models for stellar clusters, and are in agreement with the hypothesis that the star formation process leads to an initial'' binary fraction close to 100%, some systems being subsequently disrupted through the large number of encounters which occur within clusters. Optical spectroscopy of T Tauri binary systems reveals that both components of a system simultaneously possess circumstellar discs, suggesting that the environment of both stars do not evolve independently during the first million years. Direct images of two circumbinary discs and two circumstellar discs within binary systems were also obtained in the optical, the near-infrared, and the millimetric range. Coupling these observations with numerical simulations which describe photon multiple scattering allows us to estimate the geometrical characteristics of these discs, as well as the dust grain properties.
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Theses

https://tel.archives-ouvertes.fr/tel-00010389
Contributor : Gaspard Duchene <>
Submitted on : Tuesday, October 4, 2005 - 12:32:24 PM
Last modification on : Friday, November 6, 2020 - 4:02:15 AM
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### Identifiers

• HAL Id : tel-00010389, version 1

### Citation

Gaspard Duchene. Les systemes binaires jeunes et leur environnement proche: observations a haute resolution angulaire. Astrophysique [astro-ph]. Université Joseph-Fourier - Grenoble I, 2000. Français. ⟨tel-00010389⟩

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