Variable Star Working Group
This is a closely related working group. The objectives include: the estimation of the total number of variable objects detected by Gaia, the algorithm for variable object detection, the algorithm for variable object classification.

Classification Working Group (ICAP)
The goal of this working group is to develop the necessary methods to classify all of the objects observed and to determine meaningful astrophysical parameters (such as stellar effective temperatures, compositions, radii and so forth). This will make use not only of the multiband photometry, but also the parallaxes, the proper motions (e.g. for QSO detection), the radial velocity spectrum (yielding much additional information on bright targets) and variability data.