COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3341 Konkoly Observatory Budapest 21 June 1989 HU ISSN 0374-0676 OBSERVATIONS OF THE SUSPECTED VARIABLE STAR TAU CASSIOPEIAE The star tau Cassiopeiae (tau Cas, HR 9008, HD 223165, SAO 35763, K1III, V=4.87m) was observed at the University of Northern Iowa (UNI) Hillside Observatory from May 1988 until January 1989. We used a 0.4 meter Cassegrain telescope and a STARLIGHT-1 photon counting photometer with standard B and V filters. Tau Cas is listed in the New Catalogue of Suspected Variable Stars as a possible variable star (Kholopov, et al, 1982). Previous observations of tau Cas made at UNI indicate that it may be a variable star (Leiker and Hoff, 1988). HR 9010 (HD 223173, SAO 35761, K3 II, V=5.51 m, B-V=1.65) was used as the comparison star. The delta magnitudes were obtained in the sense of tau Cas-HR 9010 and are not corrected for color or extinction. Table 1 lists the mean delta magnitudes obtained for tau Cas. Each mean and standard deviation was calculated from three delta magnitudes. Standard deviation was calculated in the usual manner. See also Figures 1 and 2. [FIGURE 1] Figure 1 tau Cas Visual Delta Magnitudes [FIGURE 2] Figure 2 tau Cas Blue Delta Magnitudes Table 1 Tau Cas Visual and Blue Delta Magnitudes JD V mean sd 2447306.683 -0.713 0.045 2447317.690 -0.690 0.015 2447318.675 -0.710 0.021 2447323.682 -0.724 0.016 2447338.681 -0.684 0.002 2447359.673 -0.682 0.004 2447363.711 -0.666 0.003 2447384.641 -0.673 0.010 2447385.642 -0.674 0.010 2447389.659 -0.688 0.013 2447397.684 -0.660 0.032 2447401.746 -0.675 0.015 2447404.734 -0.675 0.004 2447405.678 -0.677 0.010 2447411.650 -0.672 0.009 2447438.656 -0.682 0.012 2447441.656 -0.681 0.010 2447442.603 -0.680 0.001 2447445.617 -0.678 0.008 2447460.674 -0.706 0.048 2447465.588 -0.662 0.006 2447466.682 -0.668 0.009 2447473.670 -0.676 0.007 2447479.546 -0.683 0.003 2447497.509 -0.678 0.010 2447498.725 -0.681 0.006 2447499.548 -0.675 0.003 2447500.524 -0.674 0.012 2447506.511 -0.683 0.007 2447553.531 -0.686 0.006 JD B mean sd 2447306.694 -1.160 0.018 2447317.701 -1.137 0.013 2447318.686 -1.170 0.012 2447323.695 -1.157 0.015 2447338.692 -1.130 0.004 2447359.682 -1.140 0.009 2447363.721 -1.138 0.002 2447384.651 -1.129 0.011 2447385.656 -1.136 0.018 2447397.695 -1.149 0.006 2447401.757 -1.133 0.006 2447404.744 -1.146 0.002 2447405.689 -1.122 0.001 2447411.666 -1.133 0.004 2447442.614 -1.127 0.011 2447465.597 -1.125 0.000 2447473.681 -1.123 0.003 2447479.556 -1.140 0.004 This work was supported in part by a computer equipment grant from a Theodore Dunham, Jr. Grant of the Fund for Astrophysical Research. P. STEVEN LEIKER Hillside Observatory Department of Earth Science University of Northern Iowa Cedar Falls, Iowa 50614-0506 USA DARREL B. HOFF Harvard-Smithsonian Center for Astrophysics 60 Garden St. Cambridge, MA 02138 USA MARY M. TUTTLE Department of Computer Science University of Northern Iowa Cedar Falls, Iowa 50614-0441 USA References: Kholopov, P. N., et al. (1982). New catalogue of suspected variable stars. Moscow: Publishing Office (Nauka). [BIBCODE 1982ncss.book.....K ] Leiker, P. S., & Hoff D. B. (1988). Is tau Cassiopeiae a variable star? Information Bulletin on Variable Stars. Number 3176.