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Origine Collisionnelle des Familles d'Astéroïdes et des Systèmes Binaires : Etude Spectroscopique et Modélisation Numérique

Abstract : A true (genetic) asteroid family is composed by fragments resulting from the disruption of a parent body, having similar orbits around the Sun. The EOS family is a dynamical cluster of more than 450 members at approximatively 3 AU from the Sun. After observing and thoroughly analyzing the visible spectra of 45 of these members, I found common and unique features, caracterizing the EOS group, and allowing a genetic family membership to be established and two interlopers to be identified. From the obtained spectral parameters I deduced that the EOS parent body was partially differentiated and that space weathering processes have played a minor role in the observed spectral diversity. Using a semi empirical model of catrastrophic breakup processes, I obtained a synthetic family of fragments simulating the Koronis family, for which the Galileo spacecraft obtained the first direct evidence of the existence of binary asteroid systems. In this context I developped a code to follow the post-breakup dynamical evolution of the fragments, taking into account the interactions, collisions and reaccumulations. The obtained results showed that the occurrence of binaries formed by couples of fragments of comparable mass is possible (about one per cent of the fragments). Finally, I studied candidates for present and future space missions. I analyzed ground based spectra of 253 Mathilde (NEAR mission), several ISO infrared spectra of selected asteroids, and groundbased spectra of candidates for the ROSETTA mission. For this last mission, I concluded that the ideal selection of asteroid targets should include 140 Siwa, which seems to be more primitive because of its size and its spectral type (C).
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Contributor : Alain Doressoundiram <>
Submitted on : Tuesday, May 11, 2004 - 4:14:46 PM
Last modification on : Wednesday, December 9, 2020 - 3:09:45 PM
Long-term archiving on: : Friday, April 2, 2010 - 8:32:16 PM


  • HAL Id : tel-00006059, version 1


Alain Doressoundiram. Origine Collisionnelle des Familles d'Astéroïdes et des Systèmes Binaires : Etude Spectroscopique et Modélisation Numérique. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 1997. Français. ⟨tel-00006059⟩



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