2003/01/16 by Alberto Vecchiato, M. G. Lattanzi, Mario G. Lattanzi +8 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Solar and Space Plasma Dynamics #astro-ph #gr-qc
paper · pdf · doi:10.1051/0004-6361:20021785
published as Astron.Astrophys.399:337-342,2003 · 7 pages, 2 figures, to be published in A&A
arxiv created 2003/01/16 · openalex publication_date 2003/02/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The global astrometric observations of a GAIA-like satellite were modeled within the PPN formulation of Post-Newtonian gravitation. An extensive experimental campaign based on realistic end-to-end simulations was conducted to establish the sensitivity of global astrometry to the PPN parameter γ, which measures the amount of space curvature produced by unit rest mass. The results show that, with just a few thousands of relatively bright, photometrically stable, and astrometrically well behaved single stars, among the ~109 objects that will be observed by GAIA, γ can be estimated after 1 year of continuous observations with an accuracy of ~10-5 at the level. Extrapolation to the full 5-year mission of these results based on the scaling properties of the adjustment procedure utilized suggests that the accuracy of , at the same level, can be reached with ~ 106 single stars, again chosen as the most astrometrically stable among the millions available in the magnitude range . These accuracies compare quite favorably with recent findings of scalar-tensor cosmological models, which predict for γ a present-time deviation, , from the General Relativity value between 10-5 and 10-7 .