COMMISSION 27 OF THE I.A.U. INFORMATION BULLETIN ON VARIABLE STARS Number 1443 Konkoly Observatory Budapest 1978 June 28 OBSERVATIONS OF THE BY DRACONIS VARIABLE GLIESE 182 The dMe star Gliese 182 (= Vyss 111) has recently been recognized as a BY Draconis variable by Bopp and Espenak (1977), who noted a range of variation in V of ~0.1 mag, with a period near two days. We report here additional photometry and spectroscopy of GL 182 obtained at CTIO in 1974 and 1975. The available data suggest a provisional rotational period P = 1.858 days for GL 182. The photometric data consist of fifteen nights of BVr photometry obtained during 1975-76 at KPNO and reported by Bopp and Espenak. In addition, twelve UBVr observations were made at CTIO during 1974-75 by Torres and Busko. These observations were done independently, and by a happy coincidence, the same comparison stars (BD +00d911, +00d915) were used. Table I gives the measured differential magnitudes DeltaV, Delta(B-V) in the sense Gliese 182 minus BD +00d915. Neither of the photometric systems was standard, and some transformation non-linearities were encountered. This may account for the discrepancy of 0.03 mag in the B-V colors. We note, however, that the internal consistency of each set of (B-V) colors is good, and no evidence for color changes over the photometric cycle is seen. In both cases, (V-r) colors could not be accurately transformed to the Johnson system, but again neither data set showed significant variability. The 1974 CTIO data appear brighter than the others by ~0.03 mag, which may reflect a real change in mean light level. For the purpose of the period analysis, we have added 0.028 mag to the 1974 data. Using all the data, we find four periods of almost equal probability: 1.833, 1.858, 2.189 and 2.199 days. Shorter periods, less than one day, do fit the data, but if these were correct, we would expect higher dispersion spectra to show rotationally broadened lines, but no line broadening is evident on 18 A mmE-1 spectrograms (Bopp and Fekel 1977). We adopt the provisional period P = 1.858 days, which is satisfied by all the data sets. We assume in this analysis that no changes in phase or period have occurred, which may not be true in general for BY Dra variables (Oskanyan et al. 1977). The data are plotted in Figure 1; zero phase is taken arbitrarily as JD 2442000. [FIGURE 1] TABLE I HJD DeltaV Delta(B-V) Observatory 2442000+ 296.890 +0.985* CTIO 297.894 0.934 CTIO 316.854 0.988 CTIO 319.886 0.924* CTIO 320.887 0.952 CTIO 701.823 1.018 +0.239 CTIO 702.819 0.948 0.238 CTIO 704.826 0.985 0.239 CTIO 705.820 0.984 0.243 CTIO 706.816 0.965 0.242 CTIO 707.830 0.957: 0.224: CTIO 709.824 0.965 0.242 CTIO 719.926 1.017 0.192 KPNO 721.013 0.968 0.202 KPNO 721.993 1.008 0.217 KPNO 722.922 0.980 0.212 KPNO 723.913 1.023 0.232 KPNO 724.921 0.946 0.204 KPNO 725.880 0.995 0.206 KPNO 727.833 1.010 0.211 KPNO 728.843 0.973 0.210 KPNO 829.648 1.002 0.192 KPNO 830.643 0.942 0.208 KPNO 831.646 0.998 0.195 KPNO 833.689 1.010 0.214 KPNO 834.640 0.967 0.203 KPNO 837.667 1.025 0.223 KPNO Differential with respect to BD +00d911 In addition, eight image tube spectrograms (dispersion 18 AmmE-1) were obtained at the coude focus of the CTIO 1.5 m reflector in 1974. The spectrograms record the Halpha region, and reveal significant night-to-night variations of the Halpha emission strength, but no correlation with the photometric period is apparent. The Li I lambda 6707 feature can be seen as a relatively strong absorption line, confirming the observations of Bopp (1974). Gliese 182 continues to be an intriguing BY Dra star: with no radial velocity variations evident, it is an apparently single star, yet its equatorial rotational velocity, assuming a two day rotational period, is -15 km sE-1, remarkably high for a single late-type dwarf. The presence of the Li I feature might suggest extreme youth, yet Gliese 182 is apparently not a member of any young cluster and is kinematically unremarkable. B. W. Bopp acknowledges support from a University of Toledo Faculty Research Award and NSF Grant AST 77-09540. B. W. BOPP Ritter Observatory University of Toledo Toledo, OH 43606 C.A.O. TORRES,* I. C. BUSKO,* AND G. R. QUAST CNPq - Observatorio Nacional Rio de Janeiro - BRASIL * Visiting Astronomer, CTIO. References: Bopp, B. W. 1974, P.A.S.P., 86, 281. [BIBCODE 1974PASP...86..281B ] Bopp, B. W., and Espenak, F. 1977, Astron. J., 82, 490. [BIBCODE 1977AJ.....82..490B ] Bopp, B. W., and Fekel, F. 1977, Astron. J., 82, 916. [BIBCODE 1977AJ.....82..916B ] Oskanyan, V. S., Evans, D. S., Lacy, C., and McMillan, R. S. 1977, Astrophys. J., 214, 430. [BIBCODE 1977ApJ...214..430O ]