In collaboration with an international group of astronomers from Europe, South America and New Zealand, Guinan and D. Bradstreet (Eastern Coll), with Villanova colleagues F. Maloney, L. DeWarf, and P. Maurone, are carrying out a multi-frequency study of faint 13th-16th mag eclipsing binaries in the Large and Small Magellanic Cloud. UV spectrophotometry of selected O/B eclipsing binaries in the LMC and SMC is chiefly being carried out with the IUE satellite. These data are combined with UBVR optical photometry to determine accurate temperatures and values of interstellar absorption for these stars. IUE spectra of 14 systems have been obtained so far. Most of the eclipsing binaries chosen are detached and consist of O- and early B-type components. In addition, about ten more eclipsing systems, serendipitously discovered by the EROS dark matter, gravitational microlensing photometric program, have been approved as targets for the 19th Episode of the IUE. These EROS eclipsing binaries are located in the Bar region of the LMC and have red and blue CCD light curves. Radial velocity observations of several of these stars are being made from South America and Australia. Additional observing time has been requested on the Hubble Space Telescope to obtain very accurate temperature and reddening determinations of a subset of these stars.
Light curves of the stars are being obtained by A. Giménez(Spain), J. V. Clausen(Den.) at the 1.5M Danish Telescope at ESO and in New Zealand by W. Tobin and J. Pritchard. Radial velocity observations are being conducted by V. Niemela (Arg.), and by Clausen, Giménez and Tobin as well as by Hilditch, Hill, and Bell.