COMMISSION 27 OF THE I. A. U.
                  INFORMATION BULLETIN ON VARIABLE STARS
                               Number 2457

                                                      Konkoly Observatory
                                                      Budapest
                                                      4 January 1984

                                                      HU ISSN 0374-0676



                 NEW PHOTOELECTRIC MINIMA TIMES OF VW CEPHEI


 VW Cep (HD 197433 = BD+75d752) is a W UMa eclipsing binary with a variable
light curve and short and long term periodic changes in its period. For these
reasons it is frequently observed.
 Photoelectric observations of VW Cep, in B and V, were carried out during
1981 and 1983. The observations were made with a two-beam, multi-mode, nebular-
stellar photometer attached to the 48-inch Cassegrain reflector at the
Kryonerion Astronomical Station of the National Observatory of Athens.
 The stars HD 192889 and HD 192635 were used for comparison and checking,
respectively. Reduction of the observations has been made using Hardie's method
(1962) and the two filters used are in close accordance with the standard
ones.
 During two observational nights (17/18 Sept. 1981 and 12/13 Sept. 1983)
the observations were carried out for several hours and thus two complete
light curves were obtained which will be appeared elsewhere. Here we shall
give the eight (8) new minima times obtained during our observations.
 Table I gives the Hel. JD of the 8 minima, the mean errors sigma, the 


                      Table I
Hel. JD     sigma     (O-C)_I   (O-C)_II   Min
2440000.+   days       days      days     Type
4859.3171  +-0.0005   -0.1189   +0.0763    I
4862.5187  +-0.0004   -0.1180   +0.0973    II
4864.4621  +_0.0004   -0.1228   +0.0724    II
4865.4454  +-0.0003   -0.1144   +0.0816    I
4865.5811  +-0.0004   -0.1171   +0.0781    II
4869.3378  +-0.0004   -0.1171   +0.0775    I
5586.4147  +-0.0006   -0.1269   -0.0912    II
5590.4471  +-0.0006   -0.1301   -0.0944    I



differences (O-C)_I and (O-C)_II and the type of minimum. The times of minima and
the mean errors have been calculated using Kwee and Van Woerden's method
(1956) and are the mean values of B and V observations. The residuals (O-C)_I
and (O-C)_II have been computed using Kwee's (1966) ephemeris formula:

       Min I = (Hel. JD) 2433898.44100+0.27831793d E

and Kukarkin's et al. (1976):

       Min I = (Hel. JD) 2433163.959+0.27831993d E,
respectively.

  The (O-C)_I values given in the foregoing Table are in good agreement with
the O-C diagram of VW Cep based on Kwee's (1966) ephemeris formula (Van't Veer,
1973, Karimie, 1983).








             P. ROVITHIS            H. ROVITHIS-LIVANIOU
             National Observatory   Astronomy Dept.
             of Athens, Athens      Athens University
             Greece                 Panepistimiopolis
                                    Athens - Greece
             




References:

Hardie, R.H.: 1962, Stars and Stellar Systems, Vol. II, Astronomical
  Techniques, ed. Hiltner, W.A., The University of Chicago Press, Chicago
Karimie, M.T.: 1983, Astrophys. Space Sci. 92, 53 [BIBCODE 1983Ap&SS..92...53K ]
Kukarkin, B.V. et al.: 1976, Third Suppl. to the Third Edition of the
  General Catalogue of Variable Stars, Moscow [BIBCODE 1976tstt.book.....K ]
Kwee, K.K.: 1966, Bull. Astron. Inst. Neth. 18, 448 [BIBCODE 1966BAN....18..448K ]
Kwee, K.K., Van Woerden, H.: 1956, Bull. Astron. Inst. Neth. 12, 327 [BIBCODE 1956BAN....12..327K ]
Van't Veer, F.: 1973, Astron. and Astrophys. 26, 357 [BIBCODE 1973A&A....26..357V ]