Determine whether astrometric and radial-velocity signals share a common companion

Establish, through joint fits to imaging, radial-velocity, and G23H astrometric data for each candidate system, whether the reported radial-velocity trends and G23H astrometric signals share a common origin in the same companion.

Background

The paper identifies 29 systems with G23H astrometric posteriors consistent with additional outer companions and notes that eight of these systems have known or tentative long-term radial-velocity variations. The analysis compares the astrometric posteriors with published radial-velocity and imaging constraints using sensitivity proxies, rather than fitting all available measurements simultaneously.

Because the separate astrometric and radial-velocity analyses do not demonstrate that the signals arise from the same physical object, the authors leave system-specific joint fits incorporating imaging, radial velocity, and astrometry for future work. Such fits are needed to test whether a single companion explains both observational signatures.

References

The astrometric posteriors provided here do not establish that the RV trends and our G23H signals share a common origin. Our goal here is simply to compare the G23H posteriors to published constraints using a common proxy for sensitivity. A joint fit with all available datasets for a given system (imaging, RV, astrometry) could establish whether the signals share a common origin. We leave these particular fits for future work.

— Astrometric Evidence for Outer Giant Planets in Known Exoplanet Systems  (2609.37160 - Ó et al., 29 Sep 2026) in Section 6.1, “Interpreting the Astrometric Candidates”