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Theses

Etude des comètes en interférométrie mililmétrique

Abstract : Comets provide clues to the physical and chemical conditions in the early Solar System. A powerful tool to image the spatial distribution of gaseous species in their inner atmosphere is from millimetre spectroscopy using interferometry techniques. Unique data were acquired in comet C/1995 O1 (Hale-Bopp) at the IRAM Plateau de Bure interferometer. During my thesis, I concentrated on the data acquired on the H2S, SO, CS and CO molecules to study their radial extension as well as the coma structure. I showed that H2S and CO are released by the nucleus. The radial distribution of CS emission is consistent with CS being produced from CS2 photolysis. The observed SO distribution is more extended than that expected if created by the photodissociation of SO2. This suggests that another source of SO is present in the coma or that at least part of SO2 is released by an extended source. The H2S outgassing is almost uniform at the nucleus surface, while part of the CS and SO molecules are concentrated in a high latitude jet. Using a physical model of the coma, I showed that the strong CO spiralling structure originating near the nucleus equator reflects a strong inhomogeneity in CO outgassing at the nucleus surface and not a shock structure created by shape and topography effects. The differences between the outgassing patterns of the different species may indicate that the nucleus composition is inhomogeneous. Tools and methods used during this study will be useful to prepare and analyse future observations of comets in millimetre interferometry.
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https://tel.archives-ouvertes.fr/tel-00232787
Contributor : Jeremie Boissier <>
Submitted on : Friday, February 1, 2008 - 5:20:02 PM
Last modification on : Friday, October 26, 2018 - 10:46:07 AM
Long-term archiving on: : Monday, May 3, 2010 - 3:18:25 PM

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  • HAL Id : tel-00232787, version 1

Citation

Jeremie Boissier. Etude des comètes en interférométrie mililmétrique. Astrophysique [astro-ph]. Université Paris-Diderot - Paris VII, 2007. Français. ⟨tel-00232787⟩

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