COMMISSIONS 27 AND 42 OF THE IAU INFORMATION BULLETIN ON VARIABLE STARS Number 3932 Konkoly Observatory Budapest 1 September 1993 HU ISSN 0374 - 0676 UBVRI MAGNITUDES FOR CATACLYSMIC VARIABLES, AF Vul AND COMPARISON STARS Observations were made at 1.25m AZT-11 telescope of the Crimean Astrophysical Observatory equipped with an UBVRI photometer-polarimeter of the Helsinki University (Korhonen et al., 1984). The stars were linked to the UBVRI-standard stars HD 195919 (Neckel & Chini, 1980), HD 161261 and HD 171732 (Barnes & Moffett, 1979). The instrumental magnitude differences were transformed to the standard UBVRI system according to the expressions obtained by N. I. Shakhovskaya (private communication): Table I -------------------------------------------------- DeltaU = 0.955DeltaU +0.218DeltaB -0.173DeltaV DeltaB = 1.173DeltaB -0.173DeltaV DeltaV = -0.104DeltaB +1.104DeltaV DeltaR = -0.104DeltaB +0.153DeltaV +0.951DeltaR DeltaB = -0.104DeltaB -0.012DeltaV +1.116DeltaI --------------------------------------------------- Moments of measurements of the variable stars are listed in Table 1 as well as references for finding charts. Because 3 standard stars were measured, we determined magnitudes by linking to each of them. Internal scatter of magnitudes is 0.07m, 0.07m, 0.05m, 0.04m and 0.02m for UBVRI, respectively. However, for colors one may obtain smaller values 0.01m for U-B and R-I and 0.02m for B-V and V-R. Deviations of colors of the two check stars BD+17d4103 and BD+11d4380 from that of Neckel & Chini (1980) are in a range from 0.01m to 0.04m which may possibly be explained by a systematic difference between the three instrumental UBVRI systems. Table II -------------------------------------------------------------- Star HJD244800 Reference for a finding chart -------------------------------------------------------------- CM Del 451.469 Meinunger (1980), Vogt & Bateson (1982) VW Vul 451.434 Vogt & Bateson (1982) EW Aql 485.323 Shain (1929) AF Vul 451.402 Wachmann (1966) V603 Aql 446.448 Williams (1983) QQ Vul 450.358 Andronov & Yavorskij (1983) MV Lyr 451.514 Andronov & Shugarov (1982) -------------------------------------------------------------- One may note an excellent coincidence of our B magnitudes for the comparison stars for AF Vul with the pg ones published by Wachmann (1966). However, there is a large difference in the value m_pg =14.8m of the star "a" for QQ Vul(Andronov & Yavorskij, 1983) with B=14.28m which may indicate systematic shift of magnitudes of other comparison stars possibly appeared due to an increased background brightness near M71 (Arp & Hartwick, 1971) which was used for photographic measurements. [FIGURE 1] Table III ------------------------------------------------------------------------------ Star U B V R I U-B B-V V-R R-I ------------------------------------------------------------------------------ CM Del 13.26 13.87 13.75 13.59 13.48 -0.61 0.12 0.16 0.11 1 13.73 13.37 12.63 12.06 11.61 0.36 0.74 0.57 0.45 2 15.30 14.14 12.96 12.10 11.42 1.16 1.18 0.86 0.68 3 14.22 13.98 13.60 13.35 13.13 0.24 0.38 0.25 0.22 4 14.92 14.77 14.54 14.31 14.07 0.15 0.23 0.23 0.24 5 14.06 13.92 13.27 12.77 12.38 0.14 0.65 0.50 0.39 6 12.69 12.52 11.97 11.50 11.15 0.17 0.55 0.47 0.35 VW Vul 15.71 16.71 16.64 15.79 15.08 1.00 0.07 0.85 0.71 1 15.60 15.37 14.64 14.06 13.55 0.23 0.72 0.58 0.51 2 14.29 13.83 12.97 12.30 11.76 0.46 0.86 0.67 0.54 3 13.59 12.56 11.36 10.49 9.76 1.03 1.20 0.87 0.73 4 13.84 12.46 11.16 10.22 9.50 1.38 1.30 0.94 0.72 5 13.33 13.24 12.67 12.21 11.83 0.09 0.57 0.46 0.38 EW Aql 12.54 12.22 11.69 11.29 11.00 0.32 0.53 0.40 0.29 1a 14.71 14.29 13.52 12.87 12.37 0.42 0.77 0.65 0.50 1b 14.50 14.08 13.32 12.68 12.13 0.42 0.76 0.64 0.55 2 14.31 13.09 11.74 10.72 9.94 1.22 1.35 1.02 0.78 3 12.75 12.03 11.17 10.47 10.02 0.72 0.86 0.70 0.45 4 15.65 15.40 14.37 13.68 13.06 0.25 1.03 0.69 0.62 AF Vul 16.37 15.76 14.52 13.65 12.94 0.61 1.24 0.87 0.71 1 14.85 14.61 14.02 13.49 13.02 0.24 0.59 0.53 0.47 2 15.73 15.00 14.14 13.36 12.76 0.73 0.86 0.78 0.60 V603 Aql 10.93 11.67 11.63 11.49 11.43 -0.74 0.04 0.14 0.06 1 10.53 10.29 9.89 9.55 9.32 0.24 0.40 0.34 0.23 QQ Vul 15.09 15.98 15.66 15.36 14.76 -0.89 0.32 0.30 0.60 1 14.48 14.28 13.58 13.03 12.63 0.20 0.70 0.55 0.40 MV Lyr 11.76 12.56 12.60 12.55 12.53 -0.80 -0.04 0.05 0.02 4 14.60 13.58 12.49 11.69 11.05 1.02 1.09 0.80 0.64 c 12.49 12.41 12.08 11.76 11.53 0.08 0.33 0.32 0.23 8 13.68 13.60 13.05 12.61 12.24 0.08 0.55 0.44 0.37 ------------------------------------------------------------------------------ Remark: Two brightness estimates of the comparison star "1" for EW Aql obtained on HJD 2448452.365 (a) and 85.330 (b) are different, despite the fact that for the star "3" they coincide within +-0.01m. For MV Lyr we had measured 3 comparison stars designated by Andronov & Shugarov (1982), who published a finding chart with 19 comparison stars. One may note a large (0.2m) systematic difference in U-magnitudes of the stars "c" and "8" as compared with that obtained with the same equipment by Andronov et al. (1992) by linking to another standard star BD+28d4211 (Neckel & Chini, 1980). Authors are thankful to Dr. N. I. Shakhovskaya for giving us reduction coefficients prior to publication and to Dr. V. Piirola for allowing to use the UBVRI photometer- polarimeter of the Helsinki University. I. L. ANDRONOV^1 I. G. BORODINA^1 S. V. KOLESNIKOV^1 N. M. SHAKHOVSKOY^2 N. A. SHVECHKOVA^1,3 1 Department of Astronomy, Odessa State University, T. G. Shevchenko Park, Odessa 270014 Ukraine 2 Crimean Astrophysical Observatory, Nauchny 334413, Crimea, Ukraine 3 Department of Astronomy and Geodesy, Ural State University, Ekaterinburg 620083 Russia References: Andronov, I. L., Borodina, I. 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