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L'ABONDANCE DU DEUTÉRIUM, DE L'ULTRAVIOLET AU VISIBLE

Abstract : In the frame of the standard Big Bang model, the primordial abundance of deuterium is the most sensitive to the baryonic density of the Universe. It was synthetized only during the primordial nucleosynthesis few minutes after the Big Bang and no other standard mechanism is able to produce any further significant amount. On the contrary, since deuterium is burned up within stars, its abundance D/H decreases along cosmic evolution. Thus, D/H measurements constrain Big Bang and galactic chemical evolution models. There are three samples of deuterium abundances : primordial, proto-solar and interstellar. Each of them is representative of a given epoch, respectively about 15 Gyrs past, 4.5 Gyrs past and present epoch. Although the evolution of the deuterium abundance seems to be qualitatively understood, the measurements show some dispersion. Present thesis works are linked to deuterium interstellar abundance measurements. Such measurements are classically obtained from spectroscopic observations of the hydrogen and deuterium Lyman series in absorption in the ultraviolet spectral range, using space observatories. Results presented here were obtained with the Hubble Space Telescope and FUSE, which has recently been launched. Simultaneously, a new way to observe deuterium has been proposed, in the visible spectral range from ground-based telescopes. This has led to the first detections and the identification of the deuterium Balmer series, in emission in HII regions, using CFHT and VLT telescopes.
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https://tel.archives-ouvertes.fr/tel-00002333
Contributor : Guillaume Hebrard <>
Submitted on : Wednesday, January 29, 2003 - 6:47:21 PM
Last modification on : Wednesday, December 9, 2020 - 3:10:44 PM
Long-term archiving on: : Tuesday, September 11, 2012 - 7:40:11 PM

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  • HAL Id : tel-00002333, version 1

Citation

Guillaume Hebrard. L'ABONDANCE DU DEUTÉRIUM, DE L'ULTRAVIOLET AU VISIBLE. Astrophysique [astro-ph]. Université Paris-Diderot - Paris VII, 2000. Français. ⟨tel-00002333⟩

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