Gaia astrometry and exoplanetary science: DR2, (E)DR3, and beyond

Abstract

I review the recent impact of Gaia astrometry in the exoplanet field, both in terms of characterization of the orbits and masses of planetary systems and the properties of their host stars. I then discuss the newly published results in the third major data release (DR3), that begin to tackle exoplanetary science based on Gaia data alone. I conclude with a perspective look at the expectations for major contributions to our understanding of exoplanet demographics from future Gaia data releases.Résumé. Je passe en revue l'impact récent de l'astrométrie fournie par la mission spatiale Gaia dans le domaine des exoplanètes, tant en termes de caractérisation des orbites et des masses des systèmes planétaires que des propriétés de leurs étoiles hôtes. Je discute ensuite des résultats récemment publiés dans la troisième livraison majeure des données (DR3), qui commencent à aborder la science des exoplanètes sur la base des seules données de Gaia. Je conclus par un regard prospectif sur les contributions majeures à notre compréhension de la démographie des exoplanètes, attendues à partir des futures publications de données Gaia.

Detection of exoplanets: exploiting each property of light

“…Such an instrument does exist and has been observing more than a billion stars since December 2013. It is GAIA, the global astrometry satellite built and operated by Europe, which, placed around the Lagrange point L2, is in the process of defining the most accurate absolute reference point ever built, as described in details in [18], in this issue of the CRAS. To do this, it is measuring very precisely the angle between two stars aimed in two very different directions (106.5°) by a pair of telescopes and this on tens of billions of indefinite pairs of stars.…”

“…Of course, there is a strong bias towards the most massive planets and those furthest from their star, as they dominate the position of the centre of gravity. At this time, the GAIA consortium has not yet announced any detections using this method, as it has been decided to wait until the end of the mission to exploit the full 100 terabyte data set for this particular scientific purpose, but projections based on actual performance give a number of detections as impressive as 21 000, or more than four times the number of exoplanets currently detected by all methods 18 .…”