COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 190 Konkoly Observatory Budapest 28 March 1967 THE PERIOD OF AB ANDROMEDAE Observations of AB And made by BAV-members in the years 1963 to 1966 show large positive O - C1's against L. BINNENDIJK's (AJ 64, 69. 1959) elements Min I = JD 243 6109. 57835 + 0.331 889 40d . E. (1) Table I: BAV-Minima of AB Andromedae Min (JD 243...) O - C1 O - C2 Observer 8983.436 +0.027 +0.003 W. Quester 8984.428 +0.024 -0.001 W. Braune .429 +0.025 0.000 W. Eckert .430 +0.026 +0.001 J. Dueball 9024.589 +0.026 +0.001 W. Braune 3026.580 +0.026 +0.001 " " 9056.442: +0.018: -0.008: M. Seidl 9058.447 +0.031 +0.006 " " 9061.434: +0.031: +0.006: " " 9063.421 +0.027 +0.002 " " 9391.324 +0.023 -0.005 " " 9403.435: +0.020: -0.008: J. Hubscher .445 +0.030 +0.002 W. Braune Using these observations and those published by L. J. ROBINSON in IBVS 180 (observer M. BALDWIN) one obtains 2 normal minima: JD 243 9024.589 O - C1 = +0.026d 9391.328 +0.027. In his work BINNENDIJK gives normal minima. These, together with some new ones, based mainly on BAV observations, are given in Table II. New elements, derived from the last 11 normal minima in Table II, are Min I = JD 2436109.57928 + 0.33189215d . E (2) +/-.00057 +/- .00000017 The residuals against these elements are given as O-C2 in Tables I and II. From the latter it can be seen that these elements sufficiently represent the observations from 1954 (JD 243 5000) onwards. In Table II roman numbers behind each time of minimum denote primary or secondary minimum, the letters e, p, v stand for photoelectrical, photographical and visual observations respectively. The variation of the period of AB And since 1900 can be followed by means of the O-C3' s in Table II. They are calculated with elements by P. Th. OOSTERHOFF (BAN 11, 217 1950) Min I = JD 242 5502.11989 + 0.331 886 486d . E. (3) The graph shows these O-C3' s plotted against time. The square represents BINNENDIJK' s photoelectrical observations; it also encloses 2 visual minima. [FIGURE 1] Table II: Normal Minima of AB Andromedae Min (JD 24. . . ) O - C2 O - C3 References 16103.925 II p +0.001d BINNENDIJK, L. 18684.512 I p +0.004 " 18963.633 I p +0.009 " 24760.360 I p +0.006 " 25276.4445 I p +0.0074 " 25502.1267 I p +0.0068 " 25873.5073 I p +0.0064 " 26216.1793 II p +0.0056 " 29523.583 I p -0.006 " 29550.6312 II p -0.0060 " 29907.7398 II p -0.0072 " 30257.8803 II p -0.0070 " 30611.8379 I p -0.0063 " 30962.645 I p -0.003 " 31046.615 I p 0.000 " 31350.4580 II p +0.0004 " 31707.9018 I p +0.0025 " 32133.0469 II p +0.0010 " 32413.1603 II p +0.0022 " 32793.671 I p +0.026d +0.005 " 33207.3684 II p +0.0200 +0.0059 " 33886.578 I v +0.012 +0.011 " 34264.600 I v +0.009 +0.013 " 35075.407 I v +0.004 +0.021 " 35304.411 I v +0.002 +0.024 RUDOLPH, R. A.N 285, 162 (190) 35370.460 I v +0.005 +0.027 BINNENDIJK loc. cit. 35379.413 I v -0.004 +0.019 RUDOLPH, loc. cit. 35782.336 I v +0.002 +0.033 BINNENDIJK, loc. cit. Min (JD 24...) O - C2 O - C3. References 37069.421 I v +0.001 +0.035 BINNENDIJK, loc. cit. 36108.418 II v 0.000 +0.036 RUDOLPH, l. c. + 1 min. EBC3 (1960) 36109.57835 I e -0.0009 +0.0345 BINNENDIJK, loc. cit. 36124.68008 II e -0.0003 +0.0354 " 36132.64609 II e +0.0003 +0.0361 " 36459.559 II v -0.001 +0.041 BRAUNE, W., QUESTER W. AN 286 209 (1963) + 2 minima EBC3 (1960) 37325.296 I v -0.004 +0.052 DUEBALL, J., LEHMANN, P. B. AN 288, 168 (1965) 37566.589 I v +0.003 +0.063 " " 37944.446 II v +0.001 +0.068 " " 39024.589 I v +0.001 +0.086 - - 39391.328 I v -0.001 +0.090 - - Berliner Arbeitsgemeinschaft fur Veranderliche Sterne (BAV) 1 Berlin 58, Buckower Chaussee 15 Germany W. QUESTER