We investigate the magnitude and characteristics of the photocentre offset phenomenon of small solar system bodies, and compare different scenarios for correcting for it. We discuss the corresponding implications and limitations to the inverse problem of model construction based on astrometry with instruments such as GAIA.

We present a combined analysis of previously published high-precision radial velocities and astrometry for the GJ 876 planetary system using a self-consistent model that accounts for the planet-planet interactions. Assuming the three planets so far identified in the system are coplanar, we find that including the astrometry in the analysis does not result in a best-fit inclination significantly...

Abstract Astrometry at centimeter wavelengths using Very Long Baseline Interferometry is approaching accuracies of ∼1 μ as for the angle between a target and calibrator source separated by ≲1° on sky. The BeSSeL Survey Japanese VERA project are this to map spiral structure Milky Way measuring trigonometric parallaxes hundreds maser sources associated with massive, young stars. This paper outlin...