Validation of Gaia DR3 astrometric binary solutions

The Gaia DR3 catalog includes 14,791 gravitationally bound wide pairs where one component is an unresolved binary with an astrometric orbital or acceleration solution. Leveraging the fact that the inner binary and outer tertiary have nearly identical parallaxes, I used these hierarchical triples to calibrate the parallax uncertainties for the astrometric solutions. I found that the uncertainties for orbital solutions are underestimated by factors of about 1.3 for faint (G > 14) stars and 1.7 for brighter stars. In addition, the uncertainties for acceleration solutions are underestimated by larger factors of 2-3. Nevertheless, both of these types of solutions represent a significant improvement over the single-star solutions for the same systems.

Read more about this research project in the associated publication here.