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Nouvelle approche du problème des forces non-gravitationnelles cométaires. Application aux comètes 19P/Borrelly et 67P/Churyumov-Gerasimenko

Abstract : When the comet approaches the Sun, the gravitational orbit of a comet is affected by the sublimation of water ice, a major component of the nucleus. This anisotropic outgassing produces a non-gravitational force that significantly changes the comet orbit. The amplitude of the perturbations depends on several parameters constrained by different observations such as astrometric and photometric data, or water production rates deduced from radio astronomy. Up to now, the modeling of these effects is mostly based on an empirical model defined in the early 70's by Marsden et al. (1973), using a simplified isotropic outgassing model. In this thesis, I developed a new physical approach to the problem of non-gravitational forces involving different physical parameters such as initial position and velocity, comet activity, direction of spin axis, mass of the nucleus and thus its density if the volume is known, a relevant parameter to understand the formation of comets. I was able to deduct their values by orbit adjustment, using photometric data. This work was applied to two comets: 19P/Borrelly for the development and the validation of my method and 67P/Churyumov-Gerasimenko the target of the European space agency mission Rosetta for which the knowledge of the mass is crucial.
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Contributor : Lucie Maquet <>
Submitted on : Tuesday, September 18, 2012 - 3:03:55 PM
Last modification on : Tuesday, December 8, 2020 - 3:36:51 AM
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  • HAL Id : tel-00733379, version 1

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Lucie Maquet. Nouvelle approche du problème des forces non-gravitationnelles cométaires. Application aux comètes 19P/Borrelly et 67P/Churyumov-Gerasimenko. Planétologie et astrophysique de la terre [astro-ph.EP]. Observatoire de Paris, 2012. Français. ⟨tel-00733379⟩

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