Program: GS-2006B-C-7

Eclipsing binaries, in which intrinsic properties of mass and radius can be measured, of young low-mass stars and brown dwarfs are essential to calibrating and testing pre-main sequence (PMS) evolutionary models. Yet only 2 subsolar PMS eclipsing systems have been published to date ([Stassun et al. 2004,2006]). We initiated the Monitor Project, a variability study of all nearby, young (<200Myr) clusters to search for low-mass eclipsing systems. We targeted the 1Myr Orion Nebula Cluster over 10 partial nights in 2004B with the 2.5m-INT+WFC. We have detected 4 candidate low-mass eclipsing systems with primary masses between 0.9 to <0.05Msun. We propose to obtain follow-up spectroscopic observations to derive radial velocity curves for the candidates. The RV curve combined with the lightcurve will provide mass and radius measurements for the individual components of the binary. The proposed data will triple the number of young late-type eclipsing binaries with known masses and radii.