Abstract
NGC 2264 is a young (∼ 3 Myr) stellar cluster that was observed twice by the CoRoT satellite, the first time for 23 days in 2008 and the second during 40 days in 2011. Simultaneous with the 2011 CoRoT observations, a multi-wavelength campaign was organized that included 30 days of Spitzer observations at 3.6 and 4.5 microns, 3.5 days of Chandra data, VLT FLAMES spectroscopy and U band photometry from Megacam (CFHT). We obtained simultaneous high precision light curves in the optical and near IR for more than 500 cluster members, about 200 of which are classical T Tauri stars. As shown in the first CoRoT campaign, a fraction of the accreting systems exhibit optical light curves with deep minima that vary substantially in width and depth in a rotational timescale. These light curves are interpreted as due to an inner disk warp that eclipses the star as the system rotates, like observed in AA Tau, a well studied CTTS seen at high inclination. This warp is thought to be created by the star-disk interaction mediated by a stellar magnetic field inclined with respect to the stellar rotation axis. The observed variability indicates the star-disk interaction is dynamic and the occulting material is inhomogeneous and located close to the co-rotation radius of the star-disk system. We present the photometric and spectroscopic analysis of the AA Tau-like CTTSs observed in NGC 2264. Initial light curve model results indicate that an inner disk warp located near the co-rotation radius can indeed explain the observed variability and that, if the variability is attributed to extinction alone, the properties of the dust in the inner disk are substantially different from the ISM.
