Strategies to photometric follow-up transiting exoplanets

It is now well ascertained that those extrasolar planets that transit in front to their parent stars deserve extensive follow-up observations because they are the only ones for which we can directly measure all their physical parameters. This information currently provides the best route to constructing the mass-radius diagram of exoplanets, which channels the theoretical formation/evolution models in the right path. However, many of the discovered transiting planets do not have high-quality light curves, so their physical properties are poorly known. In this perspective, we are leading a large program to obtain ultra-high-precision photometry of transit events, which are analyzed to accurately measure the physical properties of know planetary systems. Besides measuring and refining the physical properties of the planets and their parent stars, we also try to obtain additional information from the light curves, by identifying particular features of the systems (e.g. stellar activity) and investigating the composition of the planetary atmospheres by transmission photometry. In this conference-proceedings contribution I present several observational strategies that we adopt to achieve these goals.