COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1817

                                   Konkoly Observatory
                                   Budapest
                                   1980 July 16

        ROTHNEY ASTROPHYSICAL OBSERVATORY PUBLICATION
                  SERIES B, No. 4

           UBV PHOTOMETRY OF DN CASSIOPEIAE


   Hoffmeister (1947) first described the system as Algol type and assigned
it a period of 1.55479 days. Hiltner (1956) has classified the spectrum
as O8V. The last study of the system known to us was by Frazier and Hall
(1974) whose comparison star was found to be variable thereby compromising
the usefulness of the light curve.

   Observations were made on 9 nights during the fall of 1979 with the
40 cm reflector at the Rothney Astrophysical Observatory. An RCA 1P21
photomultiplier tube cooled to -75^o C was used with standard UBV filters.
The comparison and check stars were chosen to be BD 60deg467 and BD 60deg471
respectively. The mean square errors of the mean differential magnitudes
in V, B, and U were +-0.010, +-0.005, and +-0.007 magnitudes respectively.

   In the light curves (Figures 1-3) curvature of the maxima is apparent,
indicative of a beta Lyrae type light curve. Study of primary minimum revealed
that O-C = +0.0056 at JD 2444191.765.

   Of particular interest is the asymmetry in the maxima apparent in the
B light curve (figure 2). The secondary eclipse also appears to be asymmetric
in all three wavelengths.

   The color curves generally reveal little change from the minima suggesting
that both components are of approximately equal temperature.

   Further photometric and spectroscopic observations are being carried
out at RAO and a more complete study will appear elsewhere.

   The author would like to express appreciation to Dr. E. F. Milone and,
R. M. Robb for guidance and assistance during this study, which was begun as
a senior student research project at the University of Calgary, and is
supported by the Department of Physics at the University of Calgary and
NSERC of Canada research grants.

                          T. J. DAVIDGE
                          Rothney Astrophysical Observatory
                          Physics Department
                          University of Calgary
                          Calgary, Alberta, Canada
                          T2N 1N4

References:
1. Frazier, T.H. and Hall, D.S. 1974, P.A.S.P. 86; pp 661-667. [BIBCODE 1974PASP...86..661F ]
2. Hiltner, W.A. 1956, Ap. J. Suppl. 2, 389. [BIBCODE 1956ApJS....2..389H ]
3. Hoffmeister, C. 1947, Veroff. Sternw. Sonneberg 1, 81.

                    [FIGURE 1]
                    [FIGURE 2]
                    [FIGURE 3]