COMMISSION 27 OF THE I. A. U.
             INFORMATION BULLETIN ON VARIABLE STARS
                         Number 2270

                                                      Konkoly Observatory
                                                      Budapest
                                                      1983 January 19

                                                      HU ISSN 0374-0676


         uvby OBSERVATIONS OF HD 5303 IN OCTOBER 1981*


 The observations of the RS CVn-type southern binary HD 5303 (Collier et al.
1981) have been obtained on 12 consecutive nights of the last decade of
October 1981. The simultaneous four-colour photometer on the 50 cm Danish
telescope in ESO, La Silla, Chile (Gronbech et al. 1976) was used. Up to 40
standard stars were observed each night to tie the observations of the variable
and three auxiliary stars to the Standard uvby system. Star HD 5499 was used
as the primary comparison. The four colour indices of the auxiliary stars are
listed in Table I. The mean errors of all photometric data in that table are
typically 0.002 to 0.004.


                                     Table I
                         Auxiliary stars for HD 5303

 Star       HD       CPD         Sp   No. of      V      b-y      m1       c1
                                        nights

Comparison  5499   -74deg74    K1IV     11       6.685   0.595   0.435   0.380
Check 1     5210   -75deg66    G1/2V    11       8.691   0.375   0.193   0.299
Check 2     4815   -75deg64    K4III    5        5.081   0.847   0.740   0.402

                                      Table II
            Differential observations of HD 5303 (relative HD 5499)

MJD (hel)   Phase     DeltaV     Delta(b-y)  Deltam1  Deltac1 
                                                 
44898.106  0.814       0.842       -0.128    -0.241    -0.084
44899.079   .162       0.840       -0.131    -0.256    -0.080
44900.076   .519       0.845       -0.117    -0.269    -0.057
     .253   .582       0.818:      -0.123:   -0.244:   -0.099:
44901.112   .889       0.878       -0.124    -0.244    -0.068
44903.048   .581       0.834       -0.123    -0.281    -0.081
44904.080   .950       0.928       -0.123    -0.252    -0.073
44905.061   .300       0.795       -0.115    -0.252    -0.066
44906.086   .667       0.810       -0.113    -0.247    -0.072
44907.098   .028       0.951       -0.120    -0.238    -0.092
44908.101   .387       0.813       -0.130    -0.238    -0.071
44909.066  0.732       0.808       -0.120    -0.238    -0.069


* Based on observations obtained at the European Southern Observatory,
 La. Silla, Chile.


                           [FIGURE 1]

 Figure 1: The new observations of HD 5303 plotted together with the light
           curves of Collier at al. (1981) which were obtained in 1979 
           and 1980.

 The differential observations of HD 5303 are listed in Table II and plotted
in Fig. 1. They were obtained normally only once per night, through air-masses
between 1.44 and 1.54. The time in Table II is expressed in heliocentric modified
Julian Days (MJD = JD - 2 400 000.5). The phases have been computed from the
ephemeris given in the note added in proof in Collier et al. (1981).
 The differential data in Fig. 1 are plotted together with the light curve
copied from graphs given in Collier et al. who already noticed rather large
changes in the light curve in time-scales of a few months (this is marked
in the schematic light curves in Fig. 1). Here we would like to note a rather
substantial change in shape around the secondary minimum and a moderately
good agreement with one of the previous light curves at the primary minimum.



                   S. M. RUCINSKI
                   Institute of Astronomy
                   Madingley Road
                   Cambridge CB3 OHA, England
                   (on leave from the Warsaw University
                   Observatory)

References:


Collier, A.C., Hearnshaw, J.B., Austin, R.R.D.: 1981, Mon.Not.Roy.astr.Soc., 197, 769. [BIBCODE 1981MNRAS.197..769C ]
Gronbech, B., Olsen, E.H., Stromgren, B.: 1976, Astron.Astrophys.Suppl., 26, 155. [BIBCODE 1976A&AS...26..155G ]