An outline of the paper: Detection of transiting Jovian exoplanets by Gaia photometry – expected yield by Yifat Dzigan and Shay Zucker
Gaia is a planned European Space Agengy (ESA) mission currently being implemented with an expected launch in 2013. In ESA’s own words, its main objective will be:
To create the largest and most precise three dimensional chart of our Galaxy by providing unprecedented positional and radial velocity measurements for about one billion stars in our Galaxy and throughout the Local Group.
Gaia is expected to obtain a milli-magnitude precision in the G band for objects down to the 14th-16th magnitude, so the required precision should allow for the detection of transiting hot-Jupiters. However, due to Gaia’s low cadence combined with a small number of measurements the feasibility of detecting exoplanets becomes a non-trivial question. Dedicated transit surveys focus their efforts on observing dense star fields with a high cadence to increase the likelihood of detecting transiting planets, Gaia does not. Instead Gaia will perform an all-sky survey with a low cadence.
In the paper above the authors make an attempt at giving a more accurate and up-to-date prediction on the number of exoplanets that Gaia will be able to observe, something which will be useful when developing the Gaia analysis pipeline. Their predictions, which involve some general assumptions, show that Gaia should be able to yield detections of the order of hundreds or thousands of new planets despite the low cadence. This does not include smaller planets which they have not considered in the analysis.