PHOTOELECTRIC OBSERVATIONS OF W-UMA STARS - U-PEGASI AND AB-ANDROMEDAE

Recent photoelectric-photometric data of the W UMa systems U Pegasi and AB Andromedae are reported. From the times of minima found in the literature and those obtained in the present paper, the following quadratic ephemerides were calculated: For U Peg: HJD(min) = 2436511.6706 (+/- 0.0035) + 0.3747818 +/- 1.27 x 10(-7)) E - 1.08 x 10(-10) (+/- 0.0324 x 10(-10)) (E2/2) and for AB And: HJD(min) = 2440128.7945 (+/- 0.0035) + 0.33189162 (+/- 9 x 10(-8)) E + 8.74 x 10(-11) (+/- 0.16 x 10(-11)) (E2/2); implying a continuous change in the period of -0.91 s/century for U Peg and 0.83 s/century for AB And.