EVOLUTIONARY STATUS OF U-SAGITTAE

Using the available observational facts, the origin and evolution of t he close binary system U Sge is discussed. From a general network of s eries of medium mass close binary evolution, we derive the restriction s on masses and period. Detailed models are calculated within the deri ved ranges, giving as most likely initial parameters 3.27 M(.) + 3.25 M(.) and P-i = 1.56 d. The interactive evolution up to the present sta ge is non-conservative. We also discuss the information from the obser ved surface abundances and find them too inaccurate to exclude models.