COMMISSION 27 OF THE I. A. U.
           INFORMATION BULLETIN ON VARIABLE STARS
                       Number 2520

                                         Konkoly Observatory
                                         Budapest
                                         15 May 1984

                                         HU ISSN 0374-0676


    PHOTOELECTRIC OBSERVATIONS OF THE ECLIPSING VARIABLE BETA PERSEI

  The famous eclipsing binary system ALGOL was observed during 26 nights,
Sept.-Dec. 1983, with the new 40 cm Cassegrain telescope of Al-Battani 
Observatory, (Iraq, Tarmiya, Latitude 33d47'32" N,Longitude 44d 22'28.6"E)
using a photoelectric photometer equipped with an unrefrigerated 1P 21 
photomultiplier tube. The observations were made in UBV filters which are 
approximately in the standard system, The probable errors of a single observation
were estimated to be about +-0.01 in the three colours, i.e. corresponding
to a measure of the observational scatter at a particular phase. The variable
was observed differentially with respect to the comparison star sigma Per. The
star alpha Per was observed occasionally in order to check the comparison for
any variability but no significant variations were detected between sigma and
alpha Per.
  The raw data were reduced to about 450 points in each filter. Since the
variable and comparison were separated by about 10deg, a great care was taken
in applying the differential extinction corrections. The extinction coefficients
were calculated from the observed apparent magnitude and the outside
atmosphere magnitude of the comparison for each night, i.e., 

        ku = 0.48, kb = 0.36, kv = 0.25

Figures 1 and 2 show the UBV light curves and the colour indices U-B, B-V
for Algol, respectively. Minimum times were determined:

      J.D. Hel. 2445614.2740, O-C = 0.002 Min II
      J.D. Hel. 2445641.5135, O-C = 0.002 Min I
      J.D. Hel. 2445654.4163, O-C = 0.002 Min II

The phases of the present observations, Epochs and O-C's were calculated
according to the light elements given by Ashbrook (1976) as:

        J.D. = 2440953.4657 + 2.8673075d E



                              [FIGURE 1]

         Figure 1   UBV Light Curves for Algol (beta Persei)

                              [FIGURE 2]

         Figure 2   Colour Indices for Algol (beta Persei)


The amplitude in V was (1.27 +- 0.01) magnitude. Our observations indicate
the existence of asymmetry, especially in the beginning of the descending
part of primary minimum. The difference was approximately 0.12m, (Figure 1).
This phenomenon can be explained as a result of the presence of a gaseous
stream flowing from the secondary to the primary component, starting off
roughly in the vicinity of the inner Lagrangian point and falling behind the
primary as that star moves round in its orbit (Walter, 1980, or Al-Naimiy
and Budding, 1977).


      HAMID M.K. AL-NAIMIY, ALI A.A. MUTTER, HASSAN A. FLAIH

               and ALIA H.A. AL-ROUBAIE

           Council for Scientific Research
           Space and Astronomy Research Centre
           Jadriyah, P.O. Box 255, Baghdad,
           Iraq

References:

Al-Naimiy, H.M.K. and Budding, E.: 1977, Astrophys. Space Sci. 51, 265 [BIBCODE 1977Ap&SS..51..265A ]
Ashbrook, J.: 1976, Sky Telescope, 52, 48
Walter, K.: 1980, Astron.Astrophys. 92, 86 [BIBCODE 1980A&A....92...86W ]