Overview
The Gaia mission promises a new beginning for astrometric planet discovery. The next Gaia data release (scheduled for December 2026) will, for the first time, provide extensive time-series astrometry with a precision sufficient to detect giant planets. We have re-examined Gaia’s expected exoplanet yield using updated models for giant-planet occurrence, the local stellar population, and Gaia’s astrometric precision. This seminar will describe a semi-analytic model for the survey that clarifies key scaling relations, along with more realistic Monte Carlo simulations. We predict 7,500 ± 2,100 planet discoveries in the 5-year dataset and 120,000 ± 22,000 in the full 10-year dataset. For about a quarter of the planets, we will be able to measure masses and orbital periods to better than 20%. Most detections will be super-Jupiters on 2-5 AU orbits around GKM-type stars within 500 pc. We also present predictions for the population of false positives due to unresolved binary stars and provide mock catalogs to support community preparation for the upcoming data releases.