Photometric variability in chromospherically active stars. III - The binary stars

Differential UBV photometry of 49 late-type chromospherically active binary stars has been obtained. A total of 12,353 differential UBV magnitudes have been acquired and are used to determine seasonal photometric periods, amplitudes, mean brightnesses, maximum spot amplitudes, 'unspotted' differential magnitudes, and times of minimum light. Standard Fourier techniques are used to investigate the cause of the light variability. Eight stars are found which exhibit light variations due not to spot activity but rather to ellipticity and/or reflection effect. Others show combinations of all three effects. Some of the systems also show substantial differences between their rotational and orbital period.