COMMISSIONS 27 AND 42 OF THE IAU
           INFORMATION BULLETIN ON VARIABLE STARS
                        Number 4099

                                              Konkoly Observatory
                                              Budapest
                                              11 October 1994                      
                                              HU ISSN 0374 - 0676




          PHOTOELECTRIC OBSERVATIONS OF EP AURIGAE



EP Aur was discovered to be an eclipsing binary by Hoffmeister (1936, 1949) and 
is a  Lyr type binary with a period of 0.5910091d, Tsesevitch (1954)
gave a complete light curve, together with 9 times of photographic minima, but
no more attention was paid to this star in past 40 years. Recently, Frank (1983),
Vielmetter (1989), Moschner and Kleikamp (1990), Agerer (1991) published some 
times of minima for this star, among which only one was photoelectric observation
(Agerer, 1991), the other were photographic or visual observations.

This star was included as one of short period beta Lyr binaries of our 
observational programme and observed by using the 60 cm reflector at Xing-long
station of Beijing Astronomical Observatory from December 1990 to February
1991.

Comparison and check stars are very near to the binary. The finding chart is 
shown in Figure 1. All individual observational were corrected for differential
atmospheric extinction and transformed into standard UBV system. A total of 371
observations in each B and V colour were obtained, including one primary and
three secondary times of minima. The light curves in BV bands are shown in
Figure 2. From the light curves we can derive the depth of the primary
minimum to be about 0.7m and that of the secondary about 0.2m.

The times of minima were estimated by using Kwee-Van Woerden method. A new
ephemeris based on our new times of minima together with published minima in
literature is derived as follows:

        Min.I=HJD2448245.2312+0.59100742dxE
                         +-11       +-10


Table I. New times of minima of EP Aur.


JD(Hel.)  colour  Min.  m.e.
2400000+

48245.2373    V  I   0.0005
     .2362    B  I   0.0005
48246.1070    V  II  0.0001
     .1153    B  II  0.0008
48272.1151    V  II  0.0001
     .1175    B  II  0.0001
48273.3120    V  II  0.0009
     .3097    B  II  0.0001




                           [FIGURE 1]

 Figure 1. The finding chart of EP Aur.
 1: BD+31d 1219, 2: BD+31d 1217; 3: BD+31d 1221, 4: BD+31d 1226; 5: BD+31d 1227
 c: comparison star; ch: check star


                           [FIGURE 2]

 Figure 2. The light curves of EP Aur in BV colours.


From the O-C diagram, the period of this star is nearly constant. The times of
minima collected for this star were not enough to cover all the important parts 
of the O-C diagram, so the conclusion has to be confirmed.

A further analysis of the light curves is in progress.




Rong-xian ZHANG
Ji-tong ZHANG
Di-sheng ZHAI
Beijing Astronomical Observatory
Chinese Academy of Sciences
Beijing, 100080 China



References:

Agerer, F., 1991, BAV-Mitteilungen, No.59

Frank, P., 1983, BAV-Mitteilungen, No.36

Hoffmeister, C., 1936, Astron. Nach., 259, Nr.6195

Hoffmeister, C., 1949, Sonn. Veroff., 1, 176

Moschner, W. and Kleikamp, W., 1990, BAV-Mitteilungen, No.56

Tsesevitch, V. P., 1954, Odessa Isv., 4, 121-124

Vielmetter, H., 1989, BAV-Mitteilungen, No.52