COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3249

                                                         Konkoly Observatory
                                                         Budapest
                                                         14 October 1988

                                                         HU ISSN 0374 - 0676


            1988 BV PHOTOMETRIC OBSERVATIONS OF CG Cyg

There are several observed light curves of CG Cyg (BD +34d4217) reported
in the literature. From his visual light curve Williams (1922) suggested
irregularities outside the eclipse. It is among the eclipsing binaries with
unequal light curve maxima studied by O'Connell (1951). This star fulfills
Hall's (1976) three criteria for being a short - period RS CVn - type star,
First the period is less than one day long, (0.631141d) although it has been
shown by Milone and Ziebarth (1974) to be variable.
   Second, Naftilan and Milone (1979) studied the system spectroscopically
and found CaII H and K emission lines, and third, the two stars were classified 
as G9.5V (the hotter component) and K3 IV-V (the cooler one).
   Castle et al. (1977), Milone et al. (1979), Jassur (1980) and Naftilan
and Milone (1985) and finally Sowell et al. (1987) have also presented 
photometric observations for this star.
   The object, an eclipsing binary, was observed from 30 August through 4 
September 1988 with the 1.2 m Kryonerion Telescope and a single channel photon
counting photometer described by Dapergolas and Korakitis (1987). The photometer 
employs a high gain 9789 QB phototube and BV conventional filters.
Its output is fed directly to a microcomputer enabling rapid data access.
   The data reduction method is the standard one. The comparison and check
stars are the stars a and b, respectively named by Yu (1923). The data
were obtained with an accuracy of +/-0.015 mag.
   Table I lists the dates of observations and phases covered whereas
Figures 1 and 2 summarise the results for B and V colours.


      Table I

 Date        Phase

30-8-88    .46   .77
31-8-88    .98   .38
 1-9-88    .69   .85
 2-9-88    .19   .50
 3-9-88    .83   .96
 4-9-88    .33   .74


                            [FIGURE 1]
                            [FIGURE 2]


   Previously reported light curves show remarkable similarities and the most
notable event is the significant difference in depth between the primary
and secondary minima (~0.3 mag).
   Our data confirm these results and, in addition, we noticed that the
intrinsic scatter of the magnitudes seems larger outside the eclipse than
during them.


        A. DAPERGOLAS, E. KONTIZAS and M. KONTIZAS

             National Observatory of Athens
                Astronomical Institute
                   P.O. Box 20048
                   Athens-118 10
                       Greece



References:

Castle, K.G., Milone, E.F., Robb, R.M., and Swadrom, D.; 1977, Bull. AAS,
   9, 623. [BIBCODE 1977BAAS....9..623C ]
Dapergolas, A. and Korakitis, R., 1987, Publ. Nat. Obs. of Athens, Ser II, N28.
Hall, D.S., 1976, In: "Multiple Periodic Variable Stars" Proc. IAU Coll. No.
   29, ed.: W.S. Fitch, Vol. I. p. 287. [BIBCODE 1976ASSL...60..287H ]
Jassur, D.M.Z., 1980, Ap. Space Sci. 67, 19. [BIBCODE 1980Ap&SS..67...19J ]
Milone, E.F. and Ziebarth, K.E., 1974, Pub. Astr. Soc. of Pacific, 86, 684. [BIBCODE 1974PASP...86..684M ]
Milone, E.F., Castle, K.G., Robb, R.M., Swadrom, D., Burke, E.W., Hall, D.S.,
   Michlovic, J.E. and Zissell, R.E., 1979, Astron, J., 84, 417. [BIBCODE 1979AJ.....84..417M ]
Naftilan, S.A. and Milone, E.F., 1979, Astron. J., 84, 1218. [BIBCODE 1979AJ.....84.1218N ]
Naftilan, S.A. and Milone, E.F., 1985, Astron. J., 90, 761. [BIBCODE 1985AJ.....90..761N ]
O'Connell, D.J.K., 1951, Riverview Publ. 2(6), 85. [BIBCODE 1951PRCO....2...85O ]
Sowell, R.J., Wilson, W.J., Hall, D.S. and Peyman, C.P., 1987, PASP, 98, 407. [BIBCODE 1987PASP...99..407S ]
Yu, C.S., 1923, Astrophys. J., 58, 75. [BIBCODE 1923ApJ....58...75Y ]
Williams, A.S., 1922, Mon. Not. R. Astr. Soc., 82, 300. [BIBCODE 1922MNRAS..82..300W ]