Shapes And Dynamics Of Granular Minor Planets PDF Download

The ESA astrometric mission Gaia, due for a launch in 2011, will observe 350,000 asteroids brighter than V = 20 with an unprecedented positional precision (at the sub-milliarcsecond level for single observation). The aim of this thesis is the investigation of the science that Gaia will allow with such precise observations of asteroids and the elaboration of reduction methods for treating this future huge pool of data, in particular regarding mass determination. In the first part, we relate the characteristics of the Gaia mission and the state-of-the-art of the current asteroid mass determination. The second part describes the selection of the interesting close approaches between the few massive asteroids (perturbers) and numerous smaller asteroids (targets) in order to analyse the resulting orbital perturbations and thus, to derive the masses of the perturbers from global processing detailed in the third chapter. The expected number of asteroid masses and their associated precisions are given from realistic simulated data between 2011 and 2016. Besides, the expected precisions on the orbital elements of the targets are presented. The fourth and fifth chapters open tracks on the fundamental science from the asteroid positions with the possible derivation of the solar quadrupole moment J2, the PPN parameters β, γ, the Nordtvedt parameter η, the variation of the gravitational constant dG/dt and a study of the so-called Yarkovsky effect. The two last chapters illustrate the contribution of asteroid mass determination by Gaia to several fields of the astronomy through a study about the perturbers of Mars and the hypothetical law between density and taxonomic class.