COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2250

                                     Konkoly Observatory
                                     Budapest
                                     1982 December 17

                                     HU ISSN 0374-0676


       PHOTOMETRIC AND SPECTROSCOPIC INVESTIGATION OF Y CVn



  The famous carbon star Y CVn became the object of our photometric and
spectroscopic investigation in the past few years. The three colour BVR 
photometry of this star was provided at Brno Observatory and its high dispersion
spectra were taken with the 2m telescope of the Ondrejov Observatory. The
observational activity was directed to investigate the relationship between
the light and radial velocity changes of carbon stars.
  Our observations have led to the statement that the variations of the
radial velocity of Y CVn based on the measurements of details of the Swan
molecular bands C2(1,0) and C2(0,1) do not exceed the scale of +/- 2 km/s. They
may be connected with the light changes of the star but the observing material
due to incompleteness does not allow to give more detailed information. As
the spectroscopic observations are spread through the whole observing time
period, the photometric ones express a serious gap just near critical epoch
of the first of the three observed times of minimum light. Could perhaps
anybody complete our information on the light activity of Y CVn in the time
interval J.D. 244 4200 - 4400 ?
  The most striking feature of our photometric observations is the continuous
decrease of the B-V index of the star. Since the beginning of 1980 to the
present the star has become more blue by about 0.6 magnitude. The red colour
index V-R expresses no systematical change during the same time period.





           M. VETESNIK
           Department of Astronomy, Brno University
           61137 Brno, Czechoslovakia