COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 521


                                Konkoly Observatory
                                Budapest
                                1971 February 22


    PHOTOELECTRIC OBSERVATIONS OF THE FLARE STAR YZ CMI
DURING THE 1971 JANUARY 15 - FEBRUARY 2 INTERNATIONAL PATROL


      The photoelectric observations of the flare star
YZ CMi were carried out in the period of January 15 -
February 2, 1971. The photometer attached to the 64-cm
meniscus telescope and equipped with a blue BG-12 filter
and EMI 6256 photomultiplier was used. The total time of
continuous monitoring was 52.5 hours.
      The moments of the beginning and the end of 
continuous monitoring are given in Table I. Table II contains
the characteristics of the flares observed: time of maximum, 
durations before and after the maximum, relative 
errors of observation, integrated intensities and air masses.
We follow the notations proposed by Oskanian (IBVS No. 488).
The light curves of flares are presented on figures.


                          P.F. CHUGAINOV
                          N.I. SHAKHOVSKAYA
                   Crimean Astrophysical Observatory

                          G.N. ALEKSEEV
                      Rostov State University

                           Table I
--------------------------------------------------------------------
Date                    Coverage (UT)
--------------------------------------------------------------------
Jan.15   17 07-17 32, 17 48-17 57, 18 00-18 57, 19 13-19 37,
         19 38-19 49, 19 51-20 17, 20 20-21 04, 21 06-22 04,
         22 08-22 31, 22 32-22 41, 22 59-23 30, 23 32-24 00
Jan.16   00 00-00 07, 00 10-00 27, 00 28-02 00,(02 03-03 00),
         17 29-19 37, 19 39-20 08, 20 10-20 44, 20 46-21 24,
         21 29-22 30
Jan.18   18 47-19 52, 19 53-22 50, 22 54-23 27, 23 29-23 32,
Jan.20   22 17-22 59, 23 01-24 00
Jan.21   00 00-00 09, 19 08-19 19, 19 21-19 59, 20 00-20 32,
         20 33-23 21, 23 23-24 00
Jan.22   00 00-01 34, 01 39-01 49, 01 47-01 53, 21 15-21 52,
         22 21-23 38
Jan.25   18 47-19 59, 20 00-20 48, 20 49-21 34, 21 37-22 43,
         22 47-23 47, 23 48-24 00
Jan.26   00 00-01 34
Jan.27  (16 16-16 29, 19 29-18 21), 18 22-18 43, 18 44-19 19,
         19 25-19 51; 19 53-19 59, 20 01-20 17, 20 18-20 53,
         20 58-21 02, 21 10-23 07, 23 09-24 00
Jan.28   00 00-01 14
Jan.30   17 45-17 47, 17 49-18 31, 18 32-19 01, 19 04-19 18,
         19 19-20 43, 20 45-24 00
Jan.31   00 00-01 30, 18 23-18 41, 18 45-20 37, 20 43-22 31,
         22 39-23 40, 23 44-24 00
Feb.1    00 00-00 08
--------------------------------------------------------------------

                             Table II
-----------------------------------------------------------------------
Date
1971  UT_max    t_b    t_a                          F(z)
Jan.                        X_fm /X_s                         Remarks
                  minutes       sigma/X_s P_minutes
-----------------------------------------------------------------------
  18 22 03.1    0.2    2.7   0.37 0.042    0.26     1.34
  21 22 50.2    0.8    4.1   0.14 0.037    0.32     1.42 Possible flare
  21 23 06.0    0.7    14    0.30 0.037    0.80     1.46
  27 21 19.1    0.3    7.0   0.21 0.030    0.60     1.33
  27 21 46.5    0.2    2.8   0.13 0.042    0.13     1.35 Possible flare
  27 22 36.8    0.1    0.3   0.17 0.042    0.03     1.44  
  27 23 13.8    0.2    0.3   0.27 0.036    0.06     1.57
  30 23 36.4    0.2    0.5   0.26 0.045    0.09     1.74
  31 00 44.6    0.3    7.3   3.03 0.054    3.39     2.61
  31 20 18.8    0.3    2.4   0.12 0.041    0.16     1.34 Possible flare
-----------------------------------------------------------------------


                       [FIGURE 1]
                       [FIGURE 2]