Properties of main-sequence eclipsing binaries - Into the G stars with HS Aurigae, FL Lyrae, and EW Orionis

Spectrographic and photometric observations of three detached main sequence eclipsing binary systems with one or both components of type G, HS Aur, FL Lyr, and EW Ori, are analyzed. Ephemerides, V and R magnitudes, V-R indices, epochs, periods, e cos omega, photometric solutions, and spectrograms are presented for the systems. The radial velocities are analyzed and the orbital elements are obtained. A preliminary comparison of the systems is made with predictions from evolutionary models. HS Aur now represents a well-analyzed main sequence detached binary with both components having properties lying between those of the sun and the M1 dwarf YY Gem. In the case of FL Lyr, the two components differ significantly in their properties, making it of particular interest for its comparison with interior models and for its potential contribution to the flux and temperature scales. (Author)