2009/01/22 by Mariateresa Crosta, M. Crosta, Crosta, Mariateresa +2
Earth and Planetary Sciences · Physics and Astronomy · #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Geophysics and Gravity Measurements #History and Developments in Astronomy #Stellar, planetary, and galactic studies #gr-qc
paper · pdf · doi:10.48550/arxiv.0901.3511
22 pages, 2 figures. Submitted to Phys. Rev. D
openalex publication_date 2009/01/22 · arxiv created 2009/02/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The high accuracy of modern space astrometry requires the use of General Relativity to model the propagation of stellar light through the gravitational field encountered from a source to a given observer inside the Solar System. In this sense relativistic astrometry is part of fundamental physics. The general relativistic definition of astrometric measurement needs an appropriate use of the concept of reference frame, which should then be linked to the conventions of the IAU Resolutions (2000), which fix the celestial coordinate system. A consistent definition of the astrometric observables in the context of General Relativity is also essential to find uniquely the stellar coordinates and proper motion, this being the main physical task of the inverse ray tracing problem. Aim of this work is to set the level of reciprocal consistency of two relativistic models, GREM and RAMOD (Gaia, ESA mission), in order to garantee a physically correct definition of light direction to a star, an essential item for deducing the star coordinates and proper motion within the same level of measurement accuracy.