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Étude des processus d'altération aqueuse et de maturation des surfaces par "space weathering" des astéroïdes primitifs en support aux futures missions spatiales de retour d'échantillons

Abstract : Surface alteration processes on airless small bodies prevent the identification of primitive materials preserved since Solar System formation. Understanding how these modifications act on asteroids and change their spectra will provide a step toward better compositional interpretation of telescopic observations. This knowledge will also be valuable support for the forthcoming space missions planned to collect sample of primitive objects and bring it back to Earth. These asteroids are especially studied because they are thought to contain organic compounds and some water, key elements for life on Earth. Unaltered samples returns are crucial to precisely characterize these asteroids. Throughout my doctoral work, I studied these surface alterations -- also known as space weathering -- in order to propose a model of primitive surface maturation. I analysed spectral data from observations in the visible and near infrared ranges and find new evidence of space weathering on some specific primitive asteroid populations. Comparisons with meteorites are also made as asteroids are their parent bodies. A second approach performed in my work was to simulate space weathering effects in the laboratory using ion irradiation on meteorite samples. Such a global study on several carbonaceous chondrites had never been performed before. I show that the spectral changes are a function of initial composition. Space weathering studies must be pursued to decipher the physical, chemical and mineralogical changes it causes. I also investigated the aqueous alteration process among primitive Main Belt asteroids. Visible spectra of 600 objects were analysed to look for the absorption band indicating that liquid water had previously been present in this region of the Solar System. This study is the biggest statistical database for the aqueous alteration in the visible range. Together with recent dynamical models, these results allow us to understand the location of various compounds that originated at the time of planetary system formation and the evolution since that time.
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https://tel.archives-ouvertes.fr/tel-01267119
Contributor : Cateline Lantz Connect in order to contact the contributor
Submitted on : Wednesday, February 3, 2016 - 11:13:02 PM
Last modification on : Thursday, December 10, 2020 - 11:09:09 AM
Long-term archiving on: : Saturday, November 12, 2016 - 7:21:50 AM

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  • HAL Id : tel-01267119, version 1

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Cateline Lantz. Étude des processus d'altération aqueuse et de maturation des surfaces par "space weathering" des astéroïdes primitifs en support aux futures missions spatiales de retour d'échantillons. Planète et Univers [physics]. Université Paris Diderot, 2015. Français. ⟨tel-01267119⟩

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