COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2824 Konkoly Observatory Budapest 26 November 1985 HU ISSN 0374 - 0676 THE VARIABILITY OF HD224 559 HD 224 559 = HR9070 = LQ And is classified as a B3IV star of Beta Cep type (Borgman, 1960). Provin (1953) used it as a check star for HD224 801. Percy (1979) and Percy et al. (1981) observed HD 224 559 on nine nights altogether. They found short time-scale light variations for all single runs with amplitudes of 0.01 to 0.06 mag. The periodogram analysis shows possible time scales of 0.20 to 0.29 day with an average value of P= 0.238 +- 0.003 day. During 1978 we used this object as a second comparison star for the investigation of the Ap star HD 224 801. The observations were carried out with our twin telescope stationed at the observatory Shemakha of the Aserbaidshanian Academy of Sciences (Hildebrandt et al., 1985). During the search for short time light variations of HD224 801 we also obtained five measurement series (HD3 - HD 224 559) in the U, B, V region. The observations (Table I) were subjected to a frequency analysis using Deeming's (1975) method within the interval of periods 0.15 - 0.4 day. In all three spectral regions (U, B, V) we were able to localize two periods at the same point of the power spectrum. The best fit of the theoretical curve to the observations was realized by formula (1) when the two periods determined and their first overtones were used. 2 2 Delta m(t) = A + Sum Sum (B(kj)*sin(k*2*pi*nu(j)t) + C(kj)*cos(k*2*pi*nu(j)t)) (1) k=1 j=1 The results of the calculations for the V spectral region are summarized in Table II. For this region we obtained the smallest error for the theoretical curve. The five measurement series for the V spectral region are shown in Figure 1. The full line is the theoretical curve of the light variations of this star. Time is given in minutes of Julian day, the latter being written at the top of each figure. These results are in agreement with those of Percy. [FIGURE 1] Figure 1. Short time light variations of HD 224 559 Table I. Measurement series (HD 3 - HD 224559) Julian Date DeltaV DeltaDeltaV DeltaB DeltaDeltaB DeltaU DeltaDeltaU 43752.4151 0.1522 0.0027 0.3205 0.0030 1.0421 0.0030 43752.4301 0.1627 0.0027 0.3240 0.0029 1.0407 0.0039 43752.4436 0.1730 0.0033 0.3420 0.0034 1.0528 0.0043 43752.4580 0.1744 0.0038 0.3401 0.0026 1.0500 0.0040 43752.4722 0.1717 0.0033 0.3341 0.0025 1.0475 0.0039 43752.4869 0.1628 0.0031 0.3278 0.0036 1.0387 0.0039 43752.5008 0.1774 0.0037 0.3410 0.0036 1.0607 0.0034 43752.5149 0.1727 0.0030 0.3360 0.0035 1.0484 0.0036 43752.5300 0.1701 0.0029 0.3331 0.0026 1.0447 0.0035 43754.3903 0.1468 0.0023 0.3090 0.0031 1.0230 0.0034 43754.4048 0.1381 0.0038 0.3027 0.0035 1.0134 0.0034 43754.4194 0.1292 0.0025 0.2911 0.0023 0.9996 0.0039 43754.4336 0.1172 0.0031 0.2831 0.0030 0.9942 0.0039 43754.4484 0.1294 0.0031 0.2928 0.0032 1.0061 0.0031 43154.4646 0.1209 0.0024 0.2862 0.0029 1.0026 0.0029 43154.4794 0.1191 0.0020 0.2858 0.0025 0.9957 0.0030 43754.4941 0.1180 0.0030 0.2850 0.0025 0.9927 0.0026 43754.5098 0.1258 0.0024 0.2889 0.0030 1.0015 0.0035 43754.5261 0.1321 0.0035 0.2912 0.0037 0.9992 0.0034 43754.5425 0.1389 0.0033 0.2985 0.0034 1.0128 0.0027 43755.3885 0.1481 0.0027 0.3104 0.0024 1.0181 0.0029 43755.4028 0.1375 0.0025 0.2971 0.0020 1.0169 0.0033 43755.4176 0.1362 0.0028 0.2939 0.0026 1.0042 0.0027 43755.4320 0.1324 0.0022 0.2929 0.0024 1.0106 0.0032 43755.4461 0.1208 0.0027 0.2904 0.0029 1.0035 0.0029 43755.4604 0.1273 0.0026 0.2915 0.0021 1.0035 0.0022 49755.4743 0.1324 0.0041 0.2943 0.0032 1.0076 0.0037 43755.4886 0.1319 0.0031 0.2942 0.0030 1.0108 0.0031 43755.5025 0.1247 0.0025 0.2946 0.0030 1.0073 0.0021 43755.5176 0.1365 0.0028 0.3030 0.0022 1.0101 0.0026 43755.5324 0.1439 0.0035 0.3086 0.0025 1.0180 0.0030 43760.3855 0.1475 0.0072 0.3156 0.0063 1.0301 0.0079 43760.3739 0.1470 0.0077 0.3116 0.0064 1.0278 0.0076 43160.3886 0.1339 0.0083 0.2997 0.0065 1.0193 0.0073 43760.4028 0.1394 0.0070 0.3036 0.0069 1.0271 0.0071 43760.4191 0.1326 0.0064 0.3073 0.0061 1.0217 0.0081 43760.4368 0.1426 0.0065 0.3076 0.0059 1.0218 0.0075 43760.4525 0.1555 0.0069 0.3202 0.0065 1.0375 0.0076 43760.4682 0.1555 0.0073 0.3243 0.0058 1.0365 0.0077 43760.4843 0.1482 0.0069 0.3205 0.0066 1.0332 0.0077 43761.3763 0.1443 0.0026 0.3128 0.0024 1.0295 0.0029 43761.3911 0.1461 0.0027 0.3164 0.0029 1.0210 0.0039 43761.4340 0.1618 0.0029 0.3269 0.0029 1.0430 0.0029 43761.4484 0.1605 0.0024 0.3287 0.0022 1.0482 0.0034 43761.4631 0.1698 0.0035 0.3335 0.0040 1.0404 0.0032 43761.4774 0.1647 0.0029 0.3405 0.0029 1.0450 0.0038 43761.4915 0.1676 0.0038 0.3348 0.0028 1.0391 0.0030 43161.5060 0.1617 0.0039 0.3248 0.0028 1.0292 0.0037 43761.5201 0.1422 0.0056 0.3114 0.0041 1.0166 0.0033 Table II. Results of calculations for the V spectral region P [d] Amplitude (V) [mag] Amplitude (V) [mag] fundamental period first overtone 0.2365 0.033 0.006 0.2647 0.028 0.010 The scatter of the period and the amplitude found by him can be interpreted as a beat effect resulting from the two periods. No significant colour variation in (B-V) and (U-B) was found. The ratio of the above periods P1/P2 = 0.89 points to a non-radial pulsation but this needs confirmation by further observations. G. HILDEBRANDT Zentralinstitut fur Astrophysik Rosa-Luxemburg-Str. 17 a, DDR-1502 Potsdam-Babelsberg References: Borgman, J., 1960, Bull. Astron. Inst. Neth., 15, 255. [BIBCODE 1960BAN....15..255B ] Deeming, T.J., 1975, Astrophys. Space Sci., 36 137. [BIBCODE 1975Ap&SS..36..137D ] Hildebrandt, G., Schoneich, W., Lange, D., Zelwanowa, E., Hempelmann, A., 1985, Potsdamer Publ., 112, Bd. 32, 5. Percy, J.R., 1979, Inf. Bull. Var. Stars, No. 1530. Percy, J.R., Jakate, S.M., Matthews, J.M., 1981, Astron. J., 86, 53. [BIBCODE 1981AJ.....86...53P ] Provin, S.S., 1953, Astrophys. J., 118, 489. [BIBCODE 1953ApJ...118..489P ]