COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 758

                                  Konkoly Observatory
                                  Budapest
                                  1973 January 25


                FLARES OF YZ CMi


   The star YZ CMi (dM4.5e) was observed photoelectrically
on a total of eight nights in the period Oct.-Dec. 1972 and
the record of the effective coverage appears In Table I,
during which three flares were detected.
   The details of the characteristics of the flares and the
disc areas involved in the flare events are given in Table II.
The techniques and the procedures adopted are the same as 
employed earlier by us (Kapoor and Sinvhal, 1973).
   The flares have light curves (Figs. 1-3) more or less 
analogous to the Type II flares of Oskanyan (1969).
   The author thanks Dr. S.D. Sinvhal for his valuable 
comments and guidance.


Uttar Pradesh State Observatory
Manora Peak, Naini Tal, India.                 R.C. KAPOOR



References:

Kapoor, R.C. and Sinvhal, S.D.: 1973, I.B.V.S. (submitted). [IBVS 750]
Oskanyan, V.S.: 1969, Non-periodic Phenomena  in Variable Stars
          (Ed. L. Detre, Academic Press, Budapest), 131. [BIBCODE 1969CoKon..65..131O ]




                  TABLE I
           EFFECTIVE COVERAGE OF YZ CMi
    (Times are rounded to the nearest minute of U.T.)
--------------------------------------------------------
Date 1972
30 Oct.      19h11m-34m,     19h35m-58m,   20h00m-28m;
             20 30 -32,      20 34 -43,    20 44 -21 11;
             21 12 -14,      21 16 -44,    21 15 -22 17;
             22 20 -46,      22 47 -23 09, 23 10 -47.
 2 Nov.      19 53 -20 09,   20 17 -27,    20 32 -21 00;
             21 02 -59,      22 00 -47,    22 50 -23 38.
 6 Nov.      19 38 -20 00,   20 05 -17,    20 25 -41;
             20 52 -21 14,   21 34 -46,    21 48 -22 04;
             22 06 -13,      23 25 -44.
 8 Nov.      19 00 -22,      19 28 -40,    20 01 -06;
             20 07 -13,      20 24 -43,    22 08 -26.
13 Nov.      19 07 -17,      20 07 -16,    21 50 -22 43;
             22 46 -23 50.
 4 Dec.      17 55 -58,      18 01 -24,    18 37 -44;
             18 46 -50,      18 53 -19 06, 19 07 -14;
             19 22 -49,      19 58 -20 20, 20 22 -50;
             20 52 -21 01,   21 25 -37,    21 46 -51;
             21 52 -57,      22 40 -46,    23 01 -16;
             23 22 -41.
 6 Dec.      17 14 -47,      17 49 -18 04, 18 06 -13;
             18 15 -19,      18 20 -26,    18 42 -19 25.
11 Dec.      16 08 -09,      16 11 -22,    16 24 -17 45;
             17 57 -19 31,   19 37 -20 53, 20 55 -23 48.
--------------------------------------------------------
          (Total Coverage:  26h26m spread over 8 nights)




                  TABLE II
      CHARACTERISTICS OF THE FLARES ON YZ CMi
           (dM4.5e; V=+11.20; B-V=+1.61)
---------------------------------------------------------------------------------------------
Date              Flare Duration                                            Energy  Excess
1972              before after                                               relea-  emission
                  max.   max.                                                sed at  during
                  t_b    t_a                                                 flare   the event
                                                                             max
                                                                             10^29    10^30
       UT_mmax                 (X_fm+s)/X_s Deltam_B sigma/X_S  P_min  F_z   erg/sec  ergs
---------------------------------------------------------------------------------------------
6 Nov. 20h33m48s  2.30m  3.80m    1.98       0.74      0.027    1.41   1.47  2.15     9.20
4 Dec. 18 14 32   0.55   3.75     1.75       0.61      0.060    0.66   1.66  1.91     4.30
11Dec. 23 30 53   0.70  12.90     1.90       0.70      0.017    2.49   1.37  2.07    16.24
---------------------------------------------------------------------------------------------


                          [FIGURE 1]
                          [FIGURE 2]
                          [FIGURE 3]