COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1920 Konkoly Observatory Budapest 1981 February 6 HU ISSN 0374-0676 PHOTOELECTRIC PHOTOMETRY OF SOME Be STARS P. Harmanec et al. (1980) have recently suggested an observational photometric campaign on Be stars. As a short contribution, we present here the observations we obtained at the Loiano (Bologna) 60cm telescope, using a three channel photoelectric photometer with a S 11 EMI 9502B photomultiplier tube. The filters are the Schott standard ones for the UBV system. Because all the observations were made near the meridian, mean seasonal absorption coefficients accounting also for the second order terms were considered in order to correct the differential measurements. In the following table are reported the nightly means along with the number of individual observations. Each individual observation is the mean of four measurements of ten seconds of integration. Sometimes two nightly points were obtained. The internal scatter of the data is generally small, rarely producing a standard error on the mean amounting to more than some thousands of magnitude, thus the nightly points are accurately defined in the instrumental system. The transformation to the standard UBV system is not as satisfactory. Typical reduction errors are of 0.03m, 0.04m, 0.05m in V,B and U color. The comparison and check stars we used are reported in the short notes following the table. Their UBV magnitudes were taken from the references indicated. This research was partially supported by the National Group of Astronomy of the National Research Council (CNR). V B U n KX And 2443395.48 6.945 7.273 6.871 3 467.38 6.915 7.263 6.679 5 471.36 6.973 7.246 6.740 7 o And 2443110.39 3.604 3.514 2.991 9 395.56 3.589 3.499 2.969 3 467.34 3.607 3.514 3.008 3 472.31 3.588 3.478 3.005 5 kappa Dra 2443583.46 4.01 3.84 -4.15 + 3 639.36 3.951 3.803 -4.173 + 3 .51 3.960 3.831 -4.152 + 6 4 Her 2443631.57 5.753 5.667 3 639.44 5.756 5.682 8 .56 5.757 5.706 6 phi Per 2443109.44 4.022 3.001 10 467.45 3.958 3.938 2.803 3 471.43 3.963 3.937 2.810 8 472.35 3.963 3.938 2.808 2 BU Tau 2443472.45 5.215 4.969 2 483.45 5.222 5.185 4.979 4 HR 894 2443395.39 6.114 6.047 5.716 4 .55 6.116 6.056 5.726 2 399.55 6.116 6.043 5.713 2 471.41 6.117 6.046 5.716 4 KX And = HD218393 - Comparison star: 5 And = HD218470 (Harmanec et al. 1977); check: HD218674 (Harris, 1955) and HD 218393. The object which is probably a spectroscopic binary with strong mass transfer (Harmanec et al.1980), shows small variations in v and B colors and greater in U along with larger variations of U-B index. o And Comparison stars: HD217227 (Harris, 1955) and 2 And = HD 217782. kappa Dra Comparison star: HD109551 (Haggkvist and Oja,1966); because his U magnitude is not available, we have reported in the table the DeltaU differences (+) between the variable and the comparison star in the standard system. A little light variation seems to be present during the night 2443639. 4 Her Comparison star: HD142373 (Iriarte et al. 1965). Light fluctuations are absent in the night 2443639 during 3.6h of observations. phi Per Comparison star: 2 Per (V magnitude from Bright Star Catalogue, color indices from Crawford, 1963); Check: HD11151. The star is clearly brighter in late 1977 than in late 1976. The brightening is more notable in U color. BU Tau 28 Tau (Pleione) - Comparison star: 18 Tau = HD23324 (Iriarte et al. 1965) ; check: 16 Tau = HD23288. The star is constant during the short period of observation. HR 894 Comparison star: HD18950; check: 22pi Per = HD18411 (Iriarte et al. 1965) and 28omega Per = HD19656. We deduce the following magnitudes for the comparison star: V = 6.86 +- 0.03, B = 6.86 +- 0.03, U = 6.53 +- 0.05. During our observations the object remains perfectly constant. A. DAPERGOLAS G. DI COLA A. GUARNIERI G. MADAMA Istituto di Astronomia e Osservatorio Astronomico dell Universita di Bologna, Italy References: Crawford, D.L.: 1963 Astrophys.J., 137, 530 [BIBCODE 1963ApJ...137..530C ] Iriarte, B., Johnson, H.L., Mitchell, R.I., Wisniewski, W.K.: 1965 Sky and Tel., 30, 21. [BIBCODE 1965S&T....30...21I ] Haggkist, L. and Oia, T.: 1966, Arkiv for Astronomi, 4, 137 [BIBCODE 1966ArA.....4..137H ] Harmanec, P., Horn, J., Koubsky, P., Kriz, S., Ivanovic, Z., Pavlovski, K.: 1977 I.B.V.S. No. 1324 Harmanec, P., Horn, J., Koubsky, P., Zdarsky, F., Kriz, S., Pavlovski, K.: 1980, Bull. Astr. Inst. Czech., 31, 144 [BIBCODE 1980BAICz..31..144H ] Harris III, D.L.: 1955, Astrophys J., 121, 554 [BIBCODE 1955ApJ...121..554H ]