COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3554 Konkoly Observatory Budapest 16 January 1991 HU ISSN 0374 - 0676 FIRST PHOTOELECTRIC LIGHTCURVES IN TWO COLORS AND IMPROVED ELEMENTS FOR V482 PERSEI AND V651 CASSIOPEIAE (BAV Mitteilung Nr. 55) In this paper we report on results of our photoelectric work on two variables in Perseus and Cassiopeia. The observations were made at the private observatory of F. Agerer with an 0.35m automatic photoelectric telescope. For a description see Agerer (1988). The photometer was equipped with an uncooled EMI 9781 B PMT. Schott Filters BG12 1mm + GG 385 2mm were used for B and GG 495 1mm for V. The diaphragm measured 32". Instrumental magnitude differences were converted to the international UBV-system. Minimum timings are calculated with the Kwee - van Woerden method. V482 Persei V482 Per = BD+47d961(9.4m) = S8552 = NSV01525 was announced as variable by Hoffmeister (1966). He published time of one significant plate weakening and classified the type of variability as probably irregular. First investigation of V482 Per was conducted by Harvig and Leis (1981). They studied the variable on 237 plates from the Tartu observatory, discovered the eclipsing nature of variability with a range between 10m.90 and gave a first lightcurve. From four normal minima, together with the plate minimum by Hoffmeister, they give first elements as Min I = JD 2428327.653 + 2.446798d * E. The variable got its definitive name in the 67th name-list of variable stars (Kholopov et al. 1985). V482 Per is not comprised in the fourth edition of the General Catalogue of Variable Stars (Kholopov et al. 1987). The small extent of the observational material made us put V482 Per on our program. We observed V482 Per on 18 nights between Nov. 1988 and Nov. 1990 in B and V. BD+46d860 = SAO 039439 (F8) served as comparison star and BD+47d962 to check its constancy. Five primary and one secondary minima could be secured (Table I). Using the method of (weighted) least squares, we calculated from these timings, together with the normal minima by Harvig and Leis, the following refined elements: Min I = JD 2428327.764 + 2.4467549d * E. +-2 +-3 The lightcurve is reduced with these elements from almost 900 measurements in each colour (Fig. 1). V651 Cassiopeiae V651 Cas = BV326 = CSV8883 = NSV14717 was discovered by Strohmeier and Knigge (1960). They classify it as an eclipsing binary in the range between 11.1m and 11.6m and give a finding chart. The variable was studied again by Berthold (1983) on 193 Hartha sky-patrol plates. The author suspected W-UMa type variability and a sudden change of period occurring in Oct. 1965. First elements and a mean lightcurve with photographic magnitudes between 10.5m and 11.0m were communicated. The variable got its current name in the 67th name- list of variable stars (Kholopov et al. 1985). V651 Cas is not comprised in the fourth edition of the General Catalogue of Variable Stars (Kholopov et al. 1987). Extensive spectroscopy of the variable by Wenxian Lu (1986) showed that the period has to be doubled. New elements were given as: Min = JD 2446430.3159 + 0.996864d * E. +-22 +-41 Lu also questioned the W UMa type classification. As a consequence, Berthold (1988) re-examined the star on all Hartha sky-patrol plates and amplified this material with plates from the Sonneberg sky-patrol, covering a timespan of 54 years. From 23 deep minima Berthold published new elements: Min = JD 2446430.305 + 0.9968089d * E. +-4 +-4 To get a complete photoelectric lightcurve, we put V651 Cas on our program. V651 Cas was observed on 11 nights between Nov. 1988 and Nov. 1990 in B and V. BD+57d2816 (K0) was used as comparison star and BD+56d3093 was used to check its constancy. Three primary and three secondary minima could be observed (Table II). The depth of primary minimum is 0m.80 and that of secondary minimum is 0.31d. Using the 23 photographic minima from the revised list of Berthold (1988), the mean spectrographic epoch given by Lu and our own 6 photoelectric epochs, we calculated the new elements with the method of (weighted) least squares: Min = JD 2448205.6322 + 0.9968096d * E. +-8 +-8 The lightcurve (Fig. 2) was reduced with these elements, which are almost identical with the elements given by Berthold (1988). The slope in normal light (Fig. 3) measured on Nov. 4, 1988, which is not due to variations of the comparison star, and also the increased scatter in some parts of the lightcurve, may be due to the RS CVn characteristics of V651 Cas, which was indicated by Lu (1986). Further monitoring will be necessary to ascertain the possible presence of a low amplitude distortion wave in the light curve. [FIGURE 1] Figure 1 Differential B and V light and B-V color curves of V482 Per [FIGURE 2] Figure 2 Differential B and V light and B-V color curves of V651 Cas [FIGURE 3] Figure 3 Minimum of V651 Cas, observed on Nov. 4/5, 1988 Table 1. Observed times of minima for V982 Per, epochs and residuals computed with respect to the ephemeris derived in this paper No. JD helioc. Weight Type Epoch (O-C) Observer Source 1 2428327.655 0 P:: 0 -0.109 C. Hoffmeister AN 289.1 2 34070.291 1 F 2347 -0.006 Harwig & Leis PTAO 48.175 3 34149.808 1 F 2379.5 -0.009 4 35239.850 1 F 2825 0.004 5 35321.826 1 F 2858.5 0.013 6 2447565.3737 10 E 7862.5 -0.0006 F. Agerer this paper 7 47823.5048 10 E 7968 -0.0022 8 47840.636 5 E: 7975 0.0018 9 47850.4210 10 E 7979 -0.0003 10 47943.4012 10 E 8017 0.0032 11 48222.3268 10 E 8131 -0.0012 p denotes pg plate min., F photographic minimum and E photoelectric min. The minimum marked ":" received reduced weight, while that marked "::" was discarded. Table 2. Observed times of minima for V651 Cas, epochs and residuals computed with respect to the ephemeris derived in this paper No. JD helioc. Weight Type Epoch (O-C) Observer Source 1 2426743.311 1 p -21531 -0.013 T. Berthold MHAR 21.9 2 27060.327 1 p -21213 0.017 3 27063.324 1 p -21210 0.024 4 31413.389 1 p -16846 0.012 5 31673.534 1 p -16585 -0.011 6 33864.527 1 p -14387 -0.005 7 37888.451 1 p -14363 -0.005 8 34191.498 1 p -14059 0.012 9 35509.265 1 p -12737 -0.003 10 35551.624 1 p -12694.5 -0.009 11 36378.470 1 p -11865 -0.016 12 36394.419 1 p -11849 -0.016 17 36395.440 1 p -11848 0.008 19 36400.421 1 p -11843 0.005 15 37016.431 1 p -11225 -0.013 16 37045.351 1 p -11196 -0.001 17 39027.509 1 p -9207.5 0.001 18 39029.501 1 p -9205.5 -0.000 19 40152.403 1 p -8079 -0.004 20 44254.268 1 p -3964 -0.011 21 49256.256 1 p -3962 -0.016 22 2446430.316 5 S -1781 0.002 Wenxian Lu IBVS 2868 23 46713.391 1 p -1497 -0.017 T. Berthold MHAR 21.9 24 46714.411 1 P -1496 0.006 25 2447470.4858 10 E -737.5 0.0007 F. Agerer this paper 26 47769.5299 10 E -437.5 0.0020 27 47975.3689 10 E -231 -0.0002 28 47983.3450 10 E -223 0.0014 29 48093.4913 10 E -112.5 0.0002 30 48205.6326 10 E 0 0.0009 p denotes pg plate min.(weight 1), S the spectroscopic min. by Lu (weight 5) and E photoelectric min. (weight 10). F. AGERER D. LICHTENKNECKER + | Berliner Arbeitsgemeinschaft fur veranderliche Sterne e.V. (BAV) Munsterdamm 90, D-1000 Berlin 41 References: Agerer, F.: 1988, BAV Rundbrief 37(2), 60. Berthold, Th.: 1983, Mitt. Hartha, Heft 18. Berthold, Th.: 1988, Mitt. Hartha, Heft 21. Harvig, V., Leis, L.: 1981, Publ. Tartu Astrof. Obs. 43, 172. Hoffmeister, C.: 1966, Astron. Nachr. 289, 1. [BIBCODE 1966AN....289....1H ] Kholopov, P.N., Samus, N.N., Kazarovets, E.V., Perova, N.B.: 1985, I.B.V.S. No. 2681. Kholopov, P.N. (editor-in-chief) et al.: 1985, General Catalogue of Variable Stars, Vol. 1, Moscow: Nauka Kholopov, P.N. (editor-in-chief) et al.: 1987, General Catalogue of Variable Stars, 4th Ed., Vol. 3, Moscow: Nauka Lu, W.: 1986, I.B.V.S. No. 2868. Strohmeier, W., Knigge, R.: 1960, Veroff. Bamberg, Bd. V(5).