Digging out twin-binary star systems from the ASAS catalogue and determining their physical parameters

We have studied the ASAS catalogue in search of detached binary systems with identical components. The selected systems were photometrically and spectroscopically observed for spectral type determination. The light curves available in the ASAS database were analyzed and the light curve parameters once combined with the spectroscopic information yielded the spectral types of the binary stars in our twin candidate list. The spectral type distribution of twin binaries has shown a clear peak at the F-spectral type. Moreover, it is noteworthy that the number of twins with the A-spectral type is comparable to those with the G-spectral type, which is in contrast to previous studies.