COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1854

                                    Konkoly Observatory
                                    Budapest
                                    1980 October 13

                                    HU ISSN 0374-0676



              UBV PHOTOMETRY OF SZ Lyn



    Between December 1979 and March 1980 about 350 photoelectric
observations of the short-periodic variable SZ Lyn were carried
out with the aid of 64 cm reflector of the Crimean Astrophysical
Observatory.
    The observations were made in the UBV system with a photometer 
employing uncooled EMI 6256B tube. The standard techniques
of differential photometry were employed both in the observations
and reduction procedures.
    The comparison star was BD +45^o 1544 (V=9.43m; B-V=+0.46m;
U-B=+0.03m).
    The light and colour variations are shown in Figure 1.
    

                       [FIGURE 1]

    From the observed light curves 6 heliocentric moments of
maxima and corresponding magnitudes were determined (see Table 1).
    Differences O-C refer to the following linear elements:
          Max.hel.JD = 2438124.3977 + 0.12053481d E

given by Barnes and Moffet (1975).
  Table I
    JD_hel         O-C  B_max   V_max     (B-V)_max

2444222.3817   +0.0074d 9.330m  9.105m    0.225m
    257.4574     .0075  9.316   9.095     0.221
    261.3156     .0086  9.325   9.126     0.199
    261.4359     .0083  9.312   9.115     0.197
    262.2787     .0074  9.315   9.100     0.215
    269.2711     .0088  9.323   9.121     0.202


  As it follows from this Table there are small variations
of maximum brightness. However, we do not confirm radical changes
in the shape of maximum claimed by van Genderen (1967) and Wisse
and Wisse (1969).
  The maximum brightness changes with the phase psi of 1146
days period. Our observations are shown by open circles in
Figure 2 taken from the paper by Barnes and Moffet (1975).


                       [FIGURE 2]

The scattering in values of B_max, V_max and O-C shows the existence
of more rapid changes.
  All individual B and V light curves at the 0.4-0.6p of the
pulsation period phases show the wave, whose amplitude varies
in appreciable limits. The wave is also observed on the (B-V)
curve.
  On the basis of radial velocity determinations McNamara
et al. (1976) consider that stellar radius reaches maximum at
phase 0.4p, Consequently the wave is the result of the processes
taking place at the initial stage of the stellar compression.
  We wish to thank the authorities of the Crimean Astrophysical
Observatory for giving us the chance to get the observations.



      G.A. GARBUSOV
Odessa Astronomical Observatory

References:

McNamara,D.H., Feltz, K.A., 1976, PASP 80, No. 522, 164-167 [BIBCODE 1976PASP...88..164M ]
Barnes, T.G. and Moffet, T.J., 1975, AJ 80, 48-55 [BIBCODE 1975AJ.....80...48B ]
Wisse, M., and Wisse, P.N.J., 1969, Bull.Astron.Inst.Neth.,20,333 [BIBCODE 1969BAN....20..333W ]
van Genderen, A.M., 1967, Bull.Astron.Inst.Neth., 19, 74 [BIBCODE 1967BAN....19...74V ]