COMMISSIONS 27 AND 42 OF THE IAU 
             INFORMATION BULLETIN ON VARIABLE STARS 
                          Number 3782 
 
                                          Konkoly Observatory 
                                          Budapest 
                                          2 October 1992 
 
                                          HU ISSN 0374 - 0676 
 
 
                    THE STELLAR SYSTEM AW Cam 
 
 The star AW Cam, originally named BV 412, was discovered as a 
variable star by Strohmeier, Knigge and Ott (1963). The Cracovian 
Annual for 1992 describes it as a 8.0 magnitude star, with minima of 
amplitude 0.35m and 0.06m respectively. 
 
 Photometrically and spectroscopically it is considered that the 
principal minimum is a transit. The spectral classes of the two 
components are A0V and F2. The bigger star is also the hotter. 
 
 The Seventh Catalogue of the Orbital Elements of Spectroscopic Binary 
Systems presents its orbit as an elliptical one with: 
 
                      omega = 10deg  and e = 0.12. 
 
 This star was introduced in our observational program because until 
now the light curve determination has been very poor and the elements 
computed are not very accurate. 
 
 Our observations are performed at Bucharest Observatory with a 50cm 
Cassegrain telescope using an EMI 9502B photomultiplier. The numbers 
of the observational points are 371 in U, 372 in B and 403 in V 
filters respectively. 
 
 Using the ephemeris: 
 
                 P = 2438738.4522d + 0.7713468d x E 
 
two minima were calculated. The O-C values obtained are respectively: 
 
                  Julian Date     O-C   Min   Filter 
 
                  2445408.2819  -0.0061  I      V 
                  2447972.2460  +0.0013  I      V 
 
 We used a Wood model for the determination of the elements the 
system. Because the observational scatter is large, we have used an 
"alternate directions" method for light curve solution with six steps 
in computation. In the first two steps, we try to obtain solutions 
using two different routes to perform the differential corrections on 
the mathematical hypersurface. 
 
                (i, omega, e, a_1, k, u_2, T_2) 
 
of the solution: 
 
  [(i, a_1, k, T_2)	(omega, e)] and [(omega, e)	(i, a_1, k, T_2)], 
 
respectively, for calculating the influence of the pair (omega, e). 
The values obtained by two different routes are partly different from 
those given by Batten et al. (1978). 
 

                             [FIGURE 1]

 Figure 1. AW Cam B filter; lines - model 1, 2; pluses - obs. points

                             [FIGURE 2]

 Figure 2. AW Cam V filter; lines - model 1, 2; pluses - obs. points

                             [FIGURE 3]

 Figure 3. AW Cam U filter; lines - model 1, 2; pluses - obs. points


 The next steps were taken by an alternation of 
 
             [(u_2, T_2), (i, a_1, k, T_2)] calculations. 
 
 During this process two "relative minima" were found, with 
practically the same Summa (O-C)^2 = 0.05 values. The larger scatter 
of the observed light curve does not permit us to discriminate better 
between these two solutions. The results for the two minima in B 
filter are: 
 
ELEMENT       SOLUTION 1   SOLUTION 2 
              B            B 
 
i             78.3         78.2 
e sin omega   0.071        0.095 
e cos omega   0.040        0.046 
u_1           0.6          0.6 
u_2           0.3          0.28 
a_1           0.36         0.376 
k             0.55         0.537 
beta_1        0.25         0.25 
beta_2        0.25         0.25 
T_1           9520         9520 
T_2           5030         4687 
q             0.5          0.5 
Summa(O-C)^2  0.053        0.052 
 
 The observational UBV data will be published in Romanian Astronomical 
Journal. 

 
                          Gabriella OPRESCU and 
                          Marian Doru SURAN 
                          Astronomical Institute of the 
                          Romanian Academy 
                          Cutitul de Argint 5, 75212 Bucharest 
                          28, Romania 
 
 
References: 
 
Strohmeier, W., Knigge, R., Ott, H., 1963, Veroff. Remeis-Sternwarte 
  Bamberg, V, No. 16 
 
Batten, A. H. et al., 1978, Seventh Catalogue of the Orbital Elements 
  of Spectroscopic Binary Systems, Publ. Dom. Astrophys. Obs., 15, 
  No. 5  [BIBCODE 1978coes.book.....B ]