Optical Surveys of Young Open Clusters

Abstract

Wide field optical surveys have been proved to be a key tool to study the population of young open clusters. The avent of very large optical CCD cameras over the past 10 years allowed to obtain a complete census of the stellar population in clusters down to the substellar limit. The high efficiency of the cameras combined to their large FOV enable the survey of several hundreds to thousands cluster members in a limited amount of time, allowing in addition the study of their proper motion and variability.In this contribution I first present recent results on the low mass part of the mass function in open clusters, and discuss whether it depends on local conditions and how it evolves with age. In a second part, I present results obtained by the Monitor project, an unprecedented large scale, high cadence, photometric monitoring survey of young open clusters ideally suited to measure stellar rotation periods and constrain angular momentum evolution models.