MegaCam large program: Searching for young brown dwarf eclipsing, binaries and transiting planets in clusters
E. Moraux, S. Aigrain

Abstract: We propose to start a photometric monitoring survey of young open, clusters and star forming regions with MegaCam to search for brown, dwarf eclipsing binaries and transiting planets in the light curves of, low mass cluster members. The motivation for such a survey are, multiple and are as follow:, 1) The detection of extrasolar planets at young and well-constrained, ages with the measurements of their periods, masses and radii will, further our understanding of the formation and evolution of planetary, systems. When do planets form around stars%3F How many of them survive, this early phase%3F What is the role of environment%3F How fast do they, cool down and contract%3F, 2) By detecting young very low mass eclipsing binaries in clusters, we, will be able to measure dynamical masses and radii for objects with a, well-constrained age estimate. This will provide the anchoring points, (whose need has been recently highlighted) for theoretical, evolutionary models of young substellar objects. Systematic searches, for eclipsing binaries will also provide information on the binarity, properties of these objects, which are contain information on the star, formation process., 3) The measurement of photometric rotation periods for a large numbers, of young, low-mass objects will allow us to construct a much more, extensive database than has been possible previously in terms of, period range, stellar mass and stellar age, and with sufficient, numbers of objects to draw statistically significant conclusions. This, will help us to improve our understanding of the angular momentum, evolution of young, low mass stars. How is it redistributed and, exchanged with their surroundings %3F, 4) Finally, we will also be able to characterize and understand other, forms of intrinsic variability (e.g. flaring, micro flaring,, accretion-induced variability, stellar cycles) present in our targets., , This large scale observing project is challenging. Precise light, curves must be measured for a very large number of objects to detect, eclipses or transits as these events are rare. A large telescope, aperture is required to reach well into the brown dwarf regime in, nearby young open clusters and star forming regions in typically a, minute of integration. And high-cadence and long-term monitoring is, required to accurately measure the shape of an occultation and improve, our chances of cacthing multiple events, and to increase our, sensitivity to longer period systems., , A MegaCam large program would be perfectly suited for this project, and we feel that it could be of interest for the stellar and planet community.