Optical and X-ray light curve of the star Mon-102. The black line shows the CoRoT light curve. The time windows corresponding to the Chandra observations are the unshaded intervals. The gray dots mark the observed average X-ray photon fluxes in the broadband in the time intervals defined by setting the number of photons per interval to N_phot=20 (circled if an X-ray flare occurred during the corresponding time interval; see the figures in Appendix A). The red numbers in the top indicate the Chandra Obs.ID of the given Chandra observation.