Joint Constraints on Exoplanetary Orbits from Gaia DR3 and Doppler Data

TL;DR

This study compares Gaia DR3 astrometric exoplanet data with Doppler measurements to validate orbital solutions, revealing consistencies, inconsistencies, and refining orbital parameters for several stars.

Contribution

It provides the first joint analysis of Gaia astrometry and Doppler data for exoplanet characterization, highlighting the potential and limitations of combined datasets.

Findings

Consistent Gaia-Doppler solutions for some stars.

Inconsistencies suggest additional planets or data issues.

Refined orbital parameters for specific exoplanets.

Abstract

The third Gaia data release includes a catalog of exoplanets and exoplanet candidates identified via the star's astrometric motion. This paper reports on tests for consistency between the Gaia two-body orbital solutions and precise Doppler velocities, for the stars currently amenable to such a comparison. For BD 17-0063, HD 81040, and HD 132406, the Gaia orbital solution and the Doppler data were found to be consistent, and were fitted jointly to obtain the best possible constraints on the planets' orbits and masses. Inconsistencies were found for 4 stars: HD 111232, probably due to additional planets that were not included in the astrometric model; HD 175167 and HR 810, possibly due to inaccurate treatment of non-Gaussian uncertainties in the Gaia orbital solutions; and HIP 66074, for unknown reasons. Consistency tests were also performed for HD 114762, which was reported in 1989 to have a brown dwarf or exoplanet but has since been shown to be binary star. The joint Gaia-Doppler analysis shows the secondary mass to be 0.215 +/- 0.013 Msun and the orbital inclination to be 3.63 +/- 0.06 degrees.