COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1727

                                      Konkoly Observatory
                                      Budapest
                                      1980 January 9


       SLOW BRIGHTNESS VARIATION OF THE STAR UV Cet


During the period from 20 to 29 September 1979 a series of simultaneous
U,B,V,R,I (Lambda_eff=8200 A) observations of UV Ceti was accomplished at the
high altitude Maidanak station of the Tashkent Astronomical Institute. The
main aim of these observations was to detect flares on UV Ceti.

Some U,B,V,R,I, brightness comparison of this star were accomplished as well.
In order to exclude these comparisons during flares, simultaneous control
observations were carried out with three other telescopes. As comparison star
the star "a" (Fig. 1.) was chosen. The U,B,V,R,I magnitudes of this star have
obtained by the known magnitudes of the star HII 801 [I].

                          [FIGURE 1]

These magnitudes and corresponding errors for the star "a" are as follow:

      U                B               V                R              I
11.07m+-0.01m   10.68m+-0.01m    9.95m+-0.01m    9.32m+-0.01m    8.90m+-0.03m

The results of the observations of UV Ceti are presented in Table I.

Table I

Date of
observation    UT          U        B       V       R       I
20.9.1979     20h 30m   -        13.53m   11.68m   -       -
23.9.1979     18  50    -        13.56    -        -       -
              22  30    14.79    13.79    11.84    9.75    8.15
24.9.1979     22  00    13.92    13.46    11.90    9.70    8.17
25.9.1979     23  25    15.31    13.68    12.00    9.73    8.16
26.9.1979     17  57    15.17    -        -        -       -
              23  00    14.80    13.75    12.00    9.73    8.17
27.9.1979     17  58    14.56    13.78    12.08    9.77    8.29
              19  50    14.34    13.71    12.02    9.75    8.20
              20  00    -        -        -        -       8.30
              22  10    -        -        -        -       8.33
              22  50    15.52    13.73    12.00    9.75    8.12
28.9.1979     17  47    14.58    13.78    12.03    9.75    8.23
              22  10    14.35    -        -        -       -
              23  21    14.74    13.55    12.02    9.75    8.17
              23  30    -        13.51    -        -       -
29.9.1979     19  25    -        13.58    12.01    -       -
              21  03    -        13.54    -        -       -

The data presented in Table I show that in minimum light the brightness of UV
Ceti is significantly changing practically in all colours except maybe in R.


N.D. MELIKIAN
Byurakan Astrophysical
Observatory

N.N. KILJACHKOV, A.A. AVERIANOV
O.I. STALBOVSKY, V.S. SHEVCHENKO
N.A. SHUTIOMOVA
Tashkent Astronomical Institute

Reference:

I. Euqenio E. Mendoza V., Bol. Obs. Tonantzintla, Vol. 4, No. 28., 1967 [BIBCODE 1967BOTT....4..149M ]