COMMISSIONS 27 AND 42 OF THE IAU
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 4098

                                            Konkoly Observatory
                                            Budapest
                                            11 October 1994                      
                                            HU ISSN 0374 - 0676






       NEW PHOTOELECTRIC OBSERVATIONS FOR HL AURIGAE



HL Aur is an eclipsing binary system. It was first observed by Pfau (1955)
and Kippenhahn (1955) gave a photographic light curve and a series of time
of minima. Tsesevitch (1956), Locher (1976), Quester (1978), Frank (1983), 
Fernandes (1983), Moschner and Kleikamp (1989, 1990) published some times of 
minima. Most of them were obtained by visual or photographic observations
except for the one given by Fernandes based on photoelectric observation.

The star was observed photoelectrically on 13 nights in winter season in
1990 and 1994, respectively by using the 60 cm reflector at Xing-long station
of Beijing Astronomical Observatory.

The finding chart for comparison and check stars is shown in Figure 1. All
observational data were corrected for differential atmospheric extinction
and transformed into Johnson standard system.

Using Kwee-Van Woerden method six photoelectric times of minima were
determined (see Table 1). The 1994 light curves of HL Aur given in
Figure 2 (consisting of 150 individual observations) show that the depth
of the primary minimum is 1.07m and that of  the secondary is 0.48m and a little asymmetry
between Max I and Max II may be discovered.

We derived a new improved ephemeris by using all the recent times of minima
as follows:

                 Min.I=HJD2447913.3470+062250590dxE
                             +- 5          +- 13

From the O-C diagram the period of HL Aur is nearly constant over the past
40 years. 

                         [FIGURE 1]

Figure 1. The finding chart of HL Aur
1: BD+49d 1478; 2: BD+49d 1477; 3:BD+49d 1476; 4: BD+49d 1474


                         [FIGURE 2]

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


Table 1. New times of minima

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

47911.1722     V  II  0.0015
47911.1728     B  II  0.0013
47913.3470     V  I   0.0001
47913.3470     B  I   0.0002
47915.2162     V  I   0.0015
47915.2154     B  I   0.0007
49360.9873     V  II  0.0015
49362.2291     V  II  0.0006
49362.2274     B  II  0.0008
49363.1609     V  I   0.0005
49363.1616     B  I   0.0004





Rong-Xian ZHANG
Min-jun FANG
Ji-tong ZHANG
Di-sheng ZHAI
Bejing Astronomical Observatory
Chinese Academy of Sciences
Beijing, 100080 China




References:


Fernandes, M., 1983, BAV-Mitteilungen, No.36

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

Kippenhahn, R., 1955, Astron. Nach., 282, 73 [BIBCODE 1955AN....282...73K ]

Locher, K., 1976, BBSAG, No.21

Moschner, W., Kleikamp, W., 1989, BAV-Mitteilungen, No.52

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

Pfau, W., 1955, MVS, Sonneberg, No.198, 199

Quester, W., 1978, BAV-Mitteilungen, No.29

Tsesevitch, V. P., 1956, Astron. Circular, No.174