La population des Near-Earth Objects (NEOs) évolue sur des orbites qui peuvent croiser celle de la Terre. La plupart des NEOs proviennent de la ceinture des astéroïdes depuis des zones instables associées à des résonances puissantes ou diffusives. Les routes utilisées et les propriétés statistiques de leur dynamique ont été déterminées par intégrations numériques massives. Un modèle stationnaire des distributions de leurs orbites et de leurs magnitudes a été élaboré. Il indique que 1000 NEOs sont plus grands qu'un kilomètre et ont une fréquence d'impact avec la Terre autour de 0.5 Ma. Un mécanisme non-gravitationnel, l'effet thermique Yarkovsky, joue le rôle dominant pour délivrer du matériel dans les régions sources des NEOs, expliquant comment cette population est maintenue dans un état stationnaire et pourquoi sa distribution des tailles est moins pentue que celle produite par l'injection directe dans les résonances de fragments produits par les collisions entre astéroïdes.
The population of Near-Earth Objects (NEOs) evolves on orbits which can cross the orbit of the Earth. Most NEOs come from the asteroid belt via unstable zones associated with powerful or diffusive resonances. Their evolutionary paths and the statistical properties of their dynamics have been determined by massive numerical integrations. A steady-state model of their orbital and magnitude distributions has been elaborated which indicates that 1000 NEOs are kilometre-size with an impact frequency with the Earth around 0.5 Myr. A non-gravitational mechanism, the Yarkovsky thermal drag, plays the dominant role in delivering material in the NEO source regions, explaining how this population is maintained in a steady-state and why its size distribution is shallower than expected if NEOs were created through the direct injection of fresh fragments from collisional break ups into resonances.
Mot clés : Astéroïdes, Chaos, Dynamique, Impacts, Rencontres planétaires, Résonances
Patrick Michel 1 ; Alessandro Morbidelli 1 ; William F. Bottke 2
@article{CRPHYS_2005__6_3_291_0, author = {Patrick Michel and Alessandro Morbidelli and William F. Bottke}, title = {Origin and dynamics of {Near} {Earth} {Objects}}, journal = {Comptes Rendus. Physique}, pages = {291--301}, publisher = {Elsevier}, volume = {6}, number = {3}, year = {2005}, doi = {10.1016/j.crhy.2004.12.013}, language = {en}, }
Patrick Michel; Alessandro Morbidelli; William F. Bottke. Origin and dynamics of Near Earth Objects. Comptes Rendus. Physique, Volume 6 (2005) no. 3, pp. 291-301. doi : 10.1016/j.crhy.2004.12.013. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2004.12.013/
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