COMMISSION 27 OF THE I. A. U.
                   INFORMATION BULLETIN ON VARIABLE STARS
                                Number 2486
  
                                                        Konkoly Observatory
                                                        Budapest
                                                        6 March 1984

                                                        HU ISSN 0374 - 0676



             THE DISCOVERY OF A W URSAE MAJORIS VARIABLE IN THE
                      VISUAL BINARY SYSTEM ADS 9019



  During observations to obtain UBV data of visual binaries (Walker, 1977)
the light of the system ADS 9019 (13411+0537, or ADS 9019= BD+5d2794= SAO
120102) was discovered to be varying. Over 1200 photoelectric observations
in U, B and V have been obtained and delta magnitude curves are shown in 
Figure 1. The light curves indicate that the components form a contact binary
of the W UMa type. The observations were carried out with the 1-m Ritchey-
Chretien reflector at the Flagstaff Station.
  Visual observations of ADS 9019, made by the author with the 0.91-m 


                               [FIGURE 1]


refractor on Mt. Hamilton, indicate that it is the B component that is the 
variable. In 1979 the position angle of B relative to A was 100d, and the 
separation was 0."26. An orbit of the visual binary was computed by W. Heintz (1975)
who derived a period  of 312 years.
    The times of minimum light were determined by the Hertzsprung method (Kwee
and van Woerden, 1956). Ten observed minima were combined by least squares to
determine the light elements of the system, which are:
                   T = 244 4044.5178 + 0.40767009dE
                            +-0.0002 +-0.00000008 p.e.
The magnitudes  and colors of the system as a function of phase  are given
in Table These data include the light of  the A component. The stars  SAO
120108 and SAO 120196 were  used as the comparison and check stars, 
respectively. Their magnitudes  and colors are listed in Table II.

                 Table I. Magnitudes and Colors of ADS 9019
                   Phase      V      B-V        U-B                             
                    0.00    7.48     0.56       0.05  
                    0.25    7.06     0.55       0.04
                    0.50    7.48     0.56       0.05
                    0.75    7.06     0.55       0.04 

 Table II. Magnitudes and Colors of the Comparison and Check Stars

            Star           V     B-V      U-B      Sp(HD)
     Comp. SAO 120108    6.35    0.62     0.16       G0
     Check SAO 120196    7.12    0.93     0.57       G5

 The Wood method (Wood, 1972) was used to obtain a light curve solution
for ADS 9019 B. This solution, the data, and an analysis will be published
elsewhere. In addition a study of the relative orientation of the orbital
planes is in progress.


                               R.L. WALKER 

                           Flagstaff Station
                           U.S. Naval Observatory
                           Flagstaff, AZ 86002
                           U.S.A.

References:

Heintz, W. 1975, Circulaire d`Info., Comm. 26 of I.A.U. #66. Paris Obs., Paris.
Kwee, K.K., and van Woerden, H. 1956, Bull. Astr. Inst. Netherl., 12, 327. [BIBCODE 1956BAN....12..327K ]
Walker, R.L. 1977, Revista Mexicana de Astronomia y Astrofisica, 3, 103. [BIBCODE 1977RMxAA...3..103W ]
Wood, D.B. 1972, NASA Publ. X- 110- 72- 473.