COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2699 Konkoly Observatory Budapest 28 March 1985 HU ISSN 0374 - 0676 NSV 6044: A W UMa STAR During April 1584 a number of suspected variables were observed with the Danish 50cm telescope on Cerro La Silla, Chile. Among these was NSV 6044, the variability of which was originally discovered by Hoffmeister (1949) who designated it S4963 Cen and classified it as an Algol type variable of magnitude 9-10. The spectral type given by Houk (1982) is G5V. NSV 6044 was observed seven nights during a period of generally poor photometric quality. Nevertheless, the data can be used to obtain an ephemeris and, as the figure shows, they provide ample information on the general shape of the lightcurve, though it must be emphasized that the data are neither sufficiently numerous nor of adequate quality to justify a proper lightcurve analysis. Information on the two comparison stars used, including their uvby indices on the standard system, is listed in Table I. There is no indication of variability of the comparison stars. For the variable, average values of the indices are given in Table I and individual magnitude differences in Table II. u magnitudes have been omitted because their typical mean errors are larger than 0.01 mag and twice as large as those for y, b, and v. One time of minimum light could be determined by the method of Kwee and van Woerden (1956). The period was found by using the period analysis program of Jorgensen and Gyldenkerne (1975). The resulting ephemeris is: Min I: HJD 2445805.7721 + 0.33092d E +-1 +-1 The indices of NSV 6044 show only small variation with phase, and the mean values in the instrumental system are well [FIGURE 1] determined. Thus, the dominant contribution to the mean errors comes from the transformation. Mean errors are: sigma(b-y)- 0.09, sigma(m_1) - 0.008, and sigma(c_1) - 0.015. TABLE I Comparison 1 Comparison 2 Variable -------------------------------------------------------- HD number 112563 110653 112669 HR number - 4838 - Spectral type A3V B8/9V G5V No of obs. 92 51 75 V 6.724 6.394 9.51-10.13 b-y 0.071 -0.009 0.433 m_1 0.160 0.095 0.210 c_1 1.124 0.872 0.296 -------------------------------------------------------- Physical parameters for NSV 6044 can be estimated following the approach of Rucinski (1983) and making use of the transformations derived by Olsen (1984). This leads to a combined absolute magnitude of 3.9 and a distance of 150 pc, a reddening E(b-y) - 0.029, reddening corrected indices of (b-y)_o - 0.404, (m_1)_o = 0.219, (c_1)_o = 0.290, deltam_1 - 0.004, deltac_1 = 0.011, individual absolute magnitudes (assuming identical components) of 4.7 +- 0.1, T(eff) = 5700 K +- 100 K, [Fe/H] = -0.05 +- 0.08, log g = TABLE II: magnitude differences HD 112563 - NSV 6049 in the instrumental system ----------------------------------------------------------------------- HJD-2445000 y b v HJD-2445000 y b v ----------------------------------------------------------------------- 798.69705 2.945 3.298 3.713 801.80005 3.386 3.763 4.217 798.70014 2.925 3.271 3.689 801.80423 3.397 3.751 4.217 799.64595 3.305 3.657 4.093 801.82216 3.199 3.550 3.986 799.65002 3.315 3.687 4.122 801.82649 3.110 3.468 3.901 799.68587 2.967 3.330 3.745 801.85282 2.874 3.228 3.642 799.69044 2.929 3.293 3.718 801.85862 2.851 3.197 3.607 799.83024 3.289 3.642 4.103 801.86513 2.827 3.166 3.576 799.83396 3.211 3.586 4.023 801.87241 2.799 3.133 3.557 800.69746 2.859 3.210 3.613 801.87854 2.783 3.117 3.540 800.70237 2.841 3.190 3.600 803.59088 2.992 3.335 3.763 800.72562 2.786 3.134 3.544 803.59816 3.067 3.428 3.845 800.73053 2.789 3.131 3.540 803.85083 2.816 3.154 3.568 800.75259 2.849 3.189 3.600 803.85812 2.807 3.143 3.556 800.75736 2.874 3.221 3.637 803.86494 2.802 3.145 3.556 8U0.78011 3.077 3.432 3.860 803.87068 2.773 3.117 3.531 800.78570 3.153 3.526 3.967 805.73124 2.943 3.294 3.733 800.81463 3.378 3.751 4.191 805.73677 2.997 3.348 3.785 800.82012 3.314 3.697 4.155 805.74230 3.062 3.419 3.847 800.84468 2.990 3.326 3.743 805.74766 3.141 3.521 3.931 800.85036 2.924 3.277 3.696 805.75309 3.241 3.593 4.041 800.87906 2.791 3.133 3.547 805.75865 3.344 3.706 4.156 800.88514 2.780 3.123 3.542 805.76543 3.403 3.778 4.213 801.50670 2.972 3.327 3.745 805.77088 3.415 3.784 4.240 801.51273 2.926 3.277 3.682 805.77650 3.404 3.790 4.225 801.52561 2.863 3.210 3.631 805.78193 3.375 3.747 4.218 801.53155 2.829 3.174 3.593 805.78746 3.302 3.668 4.127 801.54930 2.782 3.127 3.528 805.79309 3.198 3.566 4.004 801.55358 2.775 3.120 3.522 805.79865 3.119 3.471 3.911 801.57114 2.796 3.135 3.548 805.80403 3.036 3.393 3.831 801.57567 2.805 3.148 3.546 805.80979 2.970 3.330 3.741 801.59371 2.889 3.243 3.639 809.51628 2.783 3.135 3.535 801.59819 2.917 3.266 3.677 809.52034 2.809 3.150 3.556 801.61674 3.134 3.486 3.903 809.57204 3.282 3.637 4.064 801.62339 3.250 3.596 4.020 809.57614 3.303 3.670 4.098 801.64395 3.279 3.647 4.066 809.58172 3.306 3.684 4.097 801.65081 3.200 3.566 3.977 801.65790 3.107 3.470 3.882 801.66513 3.019 3.375 3.795 801.77024 3.038 3.398 3.809 801.77423 3.096 3.446 3.869 ----------------------------------------------------------------------- 4.46 +- 0.06 (cgs). All these values are in good agreement with what one would expect for a G5V star, with the possible exception of M_v which is 0.4 may too bright. In conclusion, NSV 6044 is in all probability a W type W UMa variable of normal metal content and only slightly evolved away from the ZAMS (DeltaM_v = 0.14 mag). Due to the relative faintness and short period of NSV 6044 no further observations with the Danish 50 cm telescope are planned. BODIL E. HELT Copenhagen University Observatory Oster Voldgade 3 DK-1350 Copenhagen K, Denmark References: Hoffmeister, C.: 1945, Astronomische Abhandlungen. Erg. Astr. Nachr., 12, Nr. 1. Houk, N.: 1982, Michigan Catalogue of Two-Dimensional Spectral Types for the HD Stars, Vol. 3. [BIBCODE 1982mcts.book.....H ] Jorgensen, H.E., Gyldenkerne, K.: 1975, Astron. Astrophys. 44, 343. [BIBCODE 1975A&A....44..343J ] Kwee, K.K, van Woerden, H.: 1956, Bull. Astron. Inst. Neth. 12, 327, [BIBCODE 1956BAN....12..327K ] Olsen, E.H.: 1984 Astron. Astrophys, Suppl. Ser. 57, 443. [BIBCODE 1984A&AS...57..443O ] Rucinski, S.M.: 1983, Astron. Astrophys. 127, 84. [BIBCODE 1983A&A...127...84R ]