ABSOLUTE PARAMETERS FOR BINARY-SYSTEMS .2. THE LATE-TYPE SYSTEM ZZ-URSAE-MAJORIS

New light curves of the late-type binary system ZZ UMa were obtained d uring a uvby and HP monitoring program on low mass eclipsing binaries, that has been carried out in a six year photometric observational pro gram (Clement et al. 1997a, Paper I). The main goal of the program is to obtain accurate absolute parameters for stars in the low and interm ediate mass range, in order to improve the Mass-Luminosity Relationshi p (MLR) at the end of the main sequence. This paper presents a complet e analysis of the first uvby beta light curves of the late-type detach ed eclipsing binary ZZ UMa. This binary system has been observed durin g eight campaigns at the Calar Alto Observatory (Almeria, Spain).The a ctivity wave superposed on the eclipse light curve has been estimated, by using a new iterative fitting method (Clement et al. 1997b, Paper II). The interpretation of the wave suggests the existence of two acti ve zones of similar intensity, separated by areas at higher temperatur e. Once the activity wave was subtracted from the light curves, we adj usted the geometrical solution using the EBOP code. Radiative paramete rs for both stars have been derived from the light curves. Combining t he masses deduced from the radial velocity curves (Popper 1995), with the calculated geometrical and radiative values, we computed the absol ute parameters for both components. We can conclude that the system is composed of two main sequence G-type stars with masses, radii and che mical composition similar to the Sun.