A UBV photometric study of IQ Per.

About 400 UBV photoelectric observations were obtained for IQ Persei, an eclipsing binary with a visual companion. The period, heretofore unknown was found to be 1d7435673 The primary eclipse is annular, and the secondary is total but displaced, falling at . With the assumption of x8 = Xg = 0.6, a solution was secured which satisfactorily represented all three light curves. There were no photometric complications. The (U- B) and (B- V) of the hot com onent are consistent with a spectral type of B7 reddened by = . The U-B) and (B-V) ofthevisual companion are consistent with a spectral type of Al * 1 if the same amount of reddening is assumed. Both photometrically inferred spectral types are in agreement with Meisel's (1968) spectral classifications. From the ratio of the depths of the two ecli ses the spectral type of the cool comp9nent was found to be A2 2. The di erences in V among the three stars are consistent with the supposition that all three are main-sequence stars at the same distance. It would be worthwhile to obtain the spectroscopic orbital elements, to perform a least squares determination of the limb-darkening coefficients by the method of differential corrections, and to veri the predicted 70-year apsidal motion period.