COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 3312

                                         Konkoly Observatory
                                         Budapest
                                         30 March 1989

                                         HU ISSN 0374 - 0676


       V LIGHT CURVE AND ELEMENTS OF THE BINARY SYSTEM AH CEPHEI


The binary system AH Cephei was discovered and first studied as a spectroscopic
binary system by Pearce (1925). Photoelectric light curves were obtained and
the system was further studied by Zverev (1933), Stebbins (1934), Huffer and
Eggen (1947), Whitney (1956), Nekrasova (1960), Guarnieri et al. (1975),
Cester et al. (1978), Eaton (1979), Mayer (1980), Schaefer (1981), Raefert
(1982), and Mayer and Tremko (1983).

AH Cephei was observed at Bucharest in 1985-1986. The observations were made
with the 50 cm telescope and a photoelectric photometer housing an EMI
photomultiplier. The observational points in V filter are indicated by dots in
Figure 1. The star GC 31719 was used as the comparison star.


                                [FIGURE 1]


                      Table I

Year of        Source           Spectral              amplitude (m)
observations                    region        primary min.   secondary min.

1930           Huffer and Eggen   B              0.217            0.192
1930           Zverev             V              0.230            0.160
1954           Nekrasova          B              0.223            0.178
                                  V              0.233            0.193
1970           Guarnieri          B                               0.230
                                  V                               0.236
1978           Mayer              B              0.270
                                  V              0.267
1985-1986      Bucharest          B              0.290            0.260
                                  V              0.308            0.260

We used a sphere-sphere model for the first calculation of the elements of the
system. The elements were obtained simultaneously for the two minima using
Horak's minimization method. The solution was improved using a Wood model
after this first approximation. The calculated elements of the system are:

i=69.3deg   r_A=0.388     q=0.86     u=0.38     beta=0.08
e=0         r_B=0.289     a_A=0.415  a_B=0.300  L_A=0.686
omega=0     T_A=25000 K   b_A=0.385  b_B=0.287  L_B=0.313
k=0.723     T_B=22174 K   c_A=0.364  c_B=0.280

The curve in Figure 1 has been calculated with these elements. Mayer (1980)
observed that the amplitudes of the minima are increasing in time. The
Bucharest observations confirm this conclusion (see Table I). The depth of the
minima probably fluctuate due to the variable amount of circumstellar matter in
the system.  Variability of the comparison star can be ruled out.


GABRIELA OPRESCU
MARIAN DORU SURAN
NEDELIA POPESCU
Center for Astronomy and Space Sciences
5 rue Cutitul de Argint, 7000 Bucharest
Romania


References:

Cester, B., Fedel, B., Giuricin, G., Mardirossian, F., Mezzetti, M. 1978,
   Astron. Astrophys. Suppl., 33, 91.[BIBCODE 1978A&AS...33...91C ]
Eaton, J.H. 1979, Inf. Bull. Var. Stars, No. 1614.
Guarnieri, A., Bonifazi, A., Battistini, P. 1975, Astron. Astrophys. Suppl.,
   20, 199.[BIBCODE 1975A&AS...20..199G ]
Huffer C.M., Eggen, O.J. 1947, Astrophys. J., 106, 313.[BIBCODE 1947ApJ...106..313H ]
Mayer, P. 1980, Bull. Astron. Inst. Czechosl., 31, 292.[BIBCODE 1980BAICz..31..292M ]
Mayer, P., Tremko, J. 1983, Inf. Bull. Var. Stars, No. 2407.
Nekrasova, S.V. 1960, Perem. Zvezdy, 13, 157.[BIBCODE 1960PZ.....13..157N ]
Pearce, J.A. 1925, Publ. DAO Canada, 3, 171.[BIBCODE 1925PDAO....3..171P ]
Raefert, J.B. 1982, PASP, 94, 485.[BIBCODE 1982PASP...94..485R ]
Schaefer, B.E. 1981, PASP, 93, 225.[BIBCODE 1981PASP...93..225S ]
Stebbins, J. 1934, Publ. Washburn Obs., 15, 237.
Whitney, B.S. 1956, PASP, 68, 253. [BIBCODE 1956PASP...68..253W ]
Zverev, M. 1933, Perem. Zvezdy, 4, 177.