COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3442 Konkoly Observatory Budapest 9 March 1990 HU ISSN 0374 - 0676 SEVEN MORE UNDESIGNATED VARIABLE STARS A photographic sky patrol by Kaiser has resulted in the discovery of seven more variable stars that are not included in the General Catalogue of Variable Stars (Kholopov et al. 1935) or the subsequent Name Lists of Variable Stars (Kholopov et al. 1985, 1937, 1989). The positions and the preliminary magnitude ranges, types, and periods are given in Table I, which continues the list in Kaiser et al. (1989). Table I. Var. designation RA (1950) Dec (1950) Range Type P (days) DHK 6 = NSV 12178 19h 32m 36s +23d 46.7' 9.7-10.9 Lb - DHK 7 - - - - cst. - DHK 8 21 37 45 -02 00.8 9.7-11.0 b SR 343 DHK 9 03 23 03 +40 17.0 8.1- 8.6 v EA 3.045 DHK 10= NSV 2622 05 42 57 -04 15.6 12.0-12.6 b SR: 200: DHK 11 02 17 46 +54 16.9 6.9- 7.4 v EA 2.111 DHK 12= NSV 12387 19 43 44 +30 08.8 7.5- 7.9 v SRb: 60: DHK 13 19 58 28 +07 16.4 8.2- 8.6 v E: ? (The designation DHK 7 was used prematurely in AAVSO Eclipsing Binary Bulletin No. 46 to refer to a suspected eclipsing variable. However, Kaiser has re-examined the original plates and finds that the initial impression of variability was erroneous.) In this report, we present observational results for the three eclipsing systems. The four red variables will be discussed by Williams (1990). DHK 9 = BD +39 784, HD 21155, SAO 38830 (Per) The spectral type is B8. Following discovery by Kaiser, regular visual monitoring by Baldwin found additional minima at 3.05-day intervals (Baldwin and Kaiser 1989). Kaiser and Baldwin have estimated this star on 365 Harvard plates of the AI, FA, and Damon series, 1905-1948 and 1975-1989. Table II gives the times when the star was estimated to be at minimum on these plates and the Kaiser discovery photo, as well as the times of Baldwin's faintest visual estimates. Table II -- DHK 9 HJD O-C HJD O-C 2423088.478 H +0.023d 2430981.796 H -0.071d 26051.518 H -0.012 45227.756 H -0.013 27680.841 H +0.077 46488.523 H +0.001 27799.517 H -0.014 47383.841 H +0.001 28478.656 H +0.024 47502.610 K +0.004 28484.743 H +0.020 47505.664 H +0.012 28877.553 H -0.013 47636.590 B vis -0.009 30296.595 H -0.080 47718.839 B vis +0.017 30573.811 H +0.014 H = Harvard, K = Kaiser; B = Baldwin The O-C residuals refer to preliminary light elements derived from these data by the least-squares method, with mean errors: Min. I = HJD.2435938.336 + 3.0452976d E +/-.009 +/-.0000029 Two photoelectric measures by Williams near phase 0.5 of this period do not reveal a secondary minimum greater than 0.03 V. We therefore cannot eliminate the possibility that the alternate minima are primary and secondary eclipses of nearly equal depth, and the true period could be 6.09 days. The photoelectric observations are continuing. DHK 11 = BD +53 507, HD 14384, SAO 23229 (Per) The spectral type is F5V. Kaiser and Baldwin have estimated this star on 137 Harvard plates of the AI and FA series, 1938-1948, as well as Kaiser's patrol photos. The small amplitude and overexposed images make minima difficult to recognize on the long-exposure Harvard plates. Table III also includes visual timings of a predicted eclipse by each of us, derived from individual series of estimates by the tracing paper method. Table III -- DHK 11 HJD O-C HJD. O-C 2429535.713 H +0.009d 2447808.594 W vis. +0.001d 29898.776 H -0.021 47808.606 K vis +0.013 30240.798 H +0.017 47808.608 B vis +0.015 47736.826 K +0.008 47922.570 K -0.017 47789.586 K -0.008 H = Harvard, K = Kaiser, W = Williams, B = Baldwin The O-C residuals refer to the preliminary least-squares light elements: Min. I = HJD 2436324.707 + 2.1110084d E +/.006 +/.0000012 Photoelectric observations by Williams show an amplitude of 0.54 V. The eclipses are partial and 5 hours in duration. The secondary eclipse has not been observed, so the true period may be 4.2 days with equal primary and secondary minima. Photoelectric photometry by Williams and others will be reported at the end of the observing season. DHK 13 = BD +7 4335, HD 189676, SAO 125354 (AQL) The spectral type is B9. Williams has examined 4.29 Harvard plates of the AI, FA, and Damon series, 1903-1910, 1930-1946, and 1973-1988. Again, the small amplitude and long exposures makes minima very difficult to detect on the Harvard plates. The star was estimated within 0.1 magnitude of maximum on almost all plates, but five showed the star 0.4 magnitude fainter. Table IV gives these times and that of Kaiser's discovery photo. Table IV -- DHK 13 HJD HJD 2417366.755 H 2443280.798 H 18495.781 H 47356.716 H 27062.478 H 47684.848 K H = Harvard, K = Kaiser Perhaps because of the small number of minima and large time intervals we have not been able to determine an unambiguous period from these data. Williams obtained V-band photoelectric photometry for one to two hours on eight nights at the end of the 1989 observing season. The star was 0.15 magnitude fainter than maximum on one occasion and showed systematic changes of 0.03 - 0.05 magnitude on the other nights, suggesting cycles of about 0.2 day. We assume that DHK 13 is an eclipsing binary, but another type of variability may be occuring instead of, or in addition to, eclipses. Extensive photometry is planned for the next observing season to reveal the true nature of this variable. * * * We are most grateful to curator Martha Hazen for use of the Harvard College Observatory photographic plate collection, without which most of these results would not have been possible. Some of the information in this report was obtained from the SIMBAD data retrieval system, database of the Strasbourg, France, Astronomical Data Center, for which we thank Joyce Rey-Watson of the Harvard-Smithsonian Center for Astrophysics and Elizabeth Wagen of the AAVSO staff. The variables were detected by Kaiser using a projection blink comparator (PROBLICOM) as described by Mayer(1977). DANIEL H. KAISER 2631 Washington Street Columbus, IN 47201 USA MARVIN E. BALDWIN Route 1 Butlerville, IN 47223 USA DAVID B. WILLIAMS 9270-A Racquetball Way Indianopolis, IN 46260 USA REFERENCES Baldwin, M.E., and Kaiser, D.H., 1989, Journ. Amer. Assoc. Var. Star Obs. 18, 1 [BIBCODE 1989JAVSO..18....1B ] Kaiser, D.H., Williams, D.B., and Baldwin, M.E., 1989, Inform. Bull. Var. Stars No. 3313 Kholopov, P.N., editor, et al., 1985, General Catalogue of Variable Stars, Nauka, Moscow Kholopov, P.N., Samus, N.N., Kazarovets, E.V. and Perova, N.B., 1985, Inform. Bull. Var. Stars No. 2681. Kholopov, P.N., Samus, N.N., Kazarovets, E.V. and Kireeva, N.N., 1987, Inform. Bull. Var. Stars No. 3058 Kholopov, P.N., Samus, N.N., Kazarovets, E.V., Frolov, M.S., and Kireeva, N.N., 1989, Inform. Bull. Var. Stars No. 3323 Mayer, B., 1977, Sky and Telescope, 54, 246 Williams, D.B., 1990, Inform. Bull. Var. Stars No. 3443