COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 1118

                                  Konkoly Observatory
                                  Budapest
                                  1976 March 23


          PHOTOELECTRIC B, V PHOTOMETRY OF AI Hya



   The variability of the system (BD+00d2259) was discovered by
Hoffmeister (1934). The photographic magnitude of the star varies
from 9.0m to 9.5m. The star was classified as a typical Algol type
eclipsing variable by Hoffmeister. Later on four minima and light
curve of the star were photographically obtained by Lause (1938).
His light elements were
      Hel. Min.I.= J.D. 2428935.46+ 8.29d E
and distance between primary and secondary minimum, in units of
time, was 3.61d. According to Popper (1972) spectroscopic observations 
do not agree with the above period and the period must be
shorter than this value. For this purpose Popper has suggested to
obtain the light curve of the system photoelectrically.
   The star was photoelectrically observed between February 1972
and February 1973 on 17 nights with the 48 cm Cassegrain telescope
of the Ege University Observatory using an RCA 1P21 photomultiplier 
and B,V filters. BD+00d2261 was used as comparison star and
320 observational points were obtained in each colour. The star
has a long period and for this reason only a minimum could be 
obtained on 1972 April 3/4. There is a 13 hours difference between
this minimum and the calculated minimum time with Lause's light 
elements. The new light elements could not be calculated due to the
lack of available minima. Then the observed minimum time is taken
as T_0 and used the period given by Lause for the calculation of
phases:
              Hel.Min.I.= JD 2441411.368+8.29d E.

   The light and colour curves are presented in the Figure, where
the magnitude differences between the comparison and the variable
star have been plotted against the phases. The star varies about
0.590m and 0.575m at the primary, 0.500m and 0.490m at the secondary
minimum in blue and yellow light, respectively. The secondary 
minimum is really displaced from phase 0.5 and the form of the light
curve represents a typical Algol type curve as mentioned by 
Hoffmeister.

                      [FIGURE 1]

   This study is a part of research project No. 76 supported by
the Scientific and Technical Research Council of Turkey.


                            N. GUDUR
                            O. GULMEN
                            C. IBANOGLU
                            S. BOZKURT
                        Ege University Observatory
                        P.K. 21 Bornova-Izmir-Turkey.


References:
Hoffmeister, C. 1934, Astron.Nachr. 253, 195 [BIBCODE 1934AN....253..195H ]
Popper, D.M. 1972, "Second Report of the Joint Working Group of
               the IAU Com. 27 and 42"
Lause, F. 1938, Astron. Nachr. 266, 237 [BIBCODE 1938AN....266..237L ]