COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3423 Konkoly Observatory Budapest 23 January 1990 HU ISSN 0374 - 0676 PHOTOELECTRIC MINIMA OF ECLIPSING BINARIES The following table gives the photoelectric minima obtained in the years 1987 - 1989 at the N. Copernicus Observatory and Planetarium in Brno (Czechoslovakia) by means of the Nasmyth type 40-cm telescope. Measurements are made in the UBV-system, but as the signal-to-noise ratio in the U-range is not sufficient, we use the reduced BV-system. Table I gives the type of filter, the heliocentric times of minima, different values of O-C, and abbreviations of the observer's name. These abbreviations are as follows: DH : Dalibor Hanzl PS : Petr Svoboda TH : Tomas Hudecek PP : Petr Pravec Data for calculating the O-C residuals are taken from the following literature: O-C (I) : SAC 60, Krakow 1988. O-C (II) : GCVS, Moscow 1985 - 1987. Moments of the secondary minima are labeled by "s". As far as the data for calculating the times of the secondary minima were not found in the literature, we use the phase 0.5 for calculating the O-C of the secondary minima (the secondary minimum is supposed to be in mid-phase between the primary ones). In case the elements in both sources are equal, the O-C's are also equal (this is indicated by the sign = ). Table I Star Filt. Min.hel. O-C(I) O-C (II) Observer [ d ] [ d ] 24.. RT And V s 47381.4988 -0.0012 -0.0001 DH/PS B s 47381.4974 -0.0026 -0.0013 DH/PS AB And V 47063.3371 -0.0130 -0.0107 PS B 47063.3371 -0.0130 -0.0107 PS V 47413.4897 -0.0067 -0.0043 DH B 47413.4903 -0.0061 -0.0037 DH U 47413.4903 -0.0061 -0.0037 DH DS And V 47770.4524 +0.0093 = +0.0093 DH B 47770.4531 +0.0099 = +0.0099 DH OO Aql V 47061.3846 -0.0002 = -0.0002 PS/PP B 47061.3853 -0.0005 = -0.0005 PS/PP ST Aqr V 47819.3133 -0.0112 = -0.0112 DH B 47819.3119 -0.0126 = -0.0126 DH RX Ari V 47780.5104 -0.0395 -0.0114 DH B 47780.5111 -0.0388 -0.0107 DH SS Ari V 47512.3685 -0.0013 -0.0748 DH B 47512.3664 -0.0034 -0.0769 DH TY Boo V 47687.4503 +0.0084 +0.0436 DH B 47687.4509 +0.0090 +0.0442 DH i Boo V 46916.4221 -0.0008 +0.0182 PS B 46916.4207 -0.0006 +0.0182 PS U 46916.4165 -0.0048 +0.0140 PS PV Cas V s 47760.5309 +0.0133 -0.0189 DH B s 47760.5323 +0.0189 -0.0189 DH GS Cep V 47414.4346 -0.0149 = -0.0149 DH B 47414.4346 -0.0149 = -0.0149 DH U 47414.4359 -0.0137 = -0.0137 DH V 47776.4546 -0.0639 = -0.0639 DH B 47776.4539 -0.0646 = -0.0646 DH V787 Cyg V 47862.2934 -0.0018 = -0.0018 DH B 47862.3029 +0.0077 = +0.0077 DH U 47862.3002 +0.0050 = +0.0050 DH DM Del V 47791.3634 -0.0249 -0.0401 DH B 47791.3648 -0.0236 -0.0387 DH BV Dra V 47398.4240 -0.0270 -0.0135 DH B 47398.4254 -0.0256 -0.0121 DH TW Dra V 47782.4061 -0.0242 +0.0168 DH B 47782.4068 -0.0235 +0.0175 DH u Her V 47611.5207 +0.0171 = +0.0171 DH B 47611.5166 +0.0130 = +0.0130 DH V839 Oph V 47006.4936 +0.0372 +0.0456 PS B 47006.4929 +0.0365 +0.0449 PS U 47062.3199 +0.0416 +0.0437 PS/DH KW Per V 47415.4417 +0.0106 +0.0059 DH B 47415.4410 +0.0099 +0.0052 DH U 47415.4410 +0.0099 +0.0052 DH GR Tau V 47827.5148 -0.0162 -0.0055 DH B 47827.5134 -0.0176 -0.0069 DH V 47849.4363 -0.0172 -0.0066 DH/TH B 47849.4363 -0.0172 -0.0066 DH/TH V s 47856.5454 -0.0104 -0.0021 DH/TH V s 47862.5502 -0.0139 -0.0032 DH V 47889.4089 -0.0209 -0.0102 DH B 47889.4069 -0.0229 -0.0112 DH RW Tau V 47525.4486 -0.0103 -0.0311 DH B 47525.4486 -0.0103 -0.0311 DH W UMa V 46852.3907 -0.0048 -0.0051 PS FR Vul V 47713.4343 -0.0083 -0.0091 DH Remarks GR Tau: In 1989 we gained the complete light curve which, however, has not been treated yet. The first measurement showed that the information given in SAC 60, D = 1.4 h; might be incorrect (the light curve combined of six nights is shown in Figure 1). GS Cep: Elements given in SAC 60 and GCVS are probably incorrect. Some of the forecasted minima do not appear at all. This fact was found out in 1988 when the star was measured very often. We succeeded in gaining two minima only (both are given in Table I). The star is included in the Brno programme of visual observation of the eclipsing binaries but the measured fall in the range V (0.46 mag), B (0.48 mag) and U (0.47 mag) shows the inconvenience of this star for such observation. The main features of our measurement survey for this star are summarized in Table II. Table II measurement forecasted remarks begin end minimum 2447.. 2447.. 2447.. 387.385 387.597 387.4295 No minimum appeared, constant brightness. 388.364 388.599 (388.202) Constant brightness. 391.378 391.597 (391.290) Constant brightness. 392.381 392.599 (392.062) A part of rising branch at the beginning of measurement, then constant. 393.384 393.531 (393.606) Constant brightness. 398.594 398.538 (398.236) Constant brightness. 401.368 401.424 (401.326) Constant brightness. 405.519 405.563 (405.186) Constant brightness. 413.394 413.416 (413.678) Constant brightness. 414.382 414.535 414.449 Minimum appeared - see the table I. 431.316 431.391 (431.434) Constant brightness. 432.404 432.436 (432.296) Constant brightness. 439.458 439.495 (439.154) A part of rising branch (uncertain measurement because of bad wheather). 451.263 451.440 (451.507) Constant brightness. 485.384 485.444 (485.474) Constant brightness. 716.441 716.572 (716.302) Falling branch. 729.359 729.453 729.426 Rising branch (a part). 770.288 770.328 (770.343) Constant brightness. 776.386 776.538 776.519 Minimum appeared - see the table I. [FIGURE 1] Figure 1. GR Tau, V-range, BRNO 1989 (M0=44982.334; P=0.429853) The forecasted minima which are not included in the interval of measurements are given in brackets. Up to the present time the obtained data have not been published anywhere. They may be obtained directly at the Brno observatory. DALIBOR HANZL Hvezdarna a planetarium Brno 616 00 Brno Czechoslovakia