COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 666

                                          Konkoly Observatory
                                          Budapest
                                          1972 April 26


                        AD Leo


The photoelectric monitoring of the flare star AD Leo was carried out at the
Okayama Station during the period of 18 to 28 February 1972. The observations
were made with the simultaneous three-colour photometer attached to the 91 cm
reflector.

The observational results are summarized in the Table.

                                              Flares
Date       Time of          Filter   Time of     max.    P    Duration           sigma
1972      Monitoring (UT)          max. (UT)  Delta m          

Feb.19d   11h 16m  - 12h 16m   U               0.71mag  1.8min  5.0min
                               B   11h 21.8m   0.22     0.3     5.0
                               V       -         -       -       -            U 0.11^mag
                               U   11  40.5    0.48     0.6     4.5           B 0.02
                               B               0.09     0.1     4.5           V 0.02
                               V       -        -        -       -

          14  19   - 17  00    U   14  15.7    2.70    >8.0     >10
                               B               0.92    >0.9     >10
                               V               0.31    >0.3      >6
                               U   15  31.0    2.56     7.0      15
                               B               0.88     0.8      15           U 0.16
                               V               0.29     0.3      15           B 0.03
                               U   16  45.5    1.98                           V 0.03
                               B   16  45.5    0.57   U >21.4>22
                               V   16  45.7    0.18   B > 3.2>22
                               U   16  46.1    1.90   V > 1.2>22
                               B   16  46.1    0.58
                               V   16  46.2    0.20

    20    10  39   - 12 00
          12  26   - 13 00
          13  38   - 14 05
          15  06   - 15 34
          17  07   - 17 36     U               0.92     1.7     4.0             0.16
                               B   17  29.7    0.20     0.3     4.0             0.05
                               V               0.05     1.0     1.8             0.02

    23    11  07   - 17  11    U               1.47     8.3    15.0             0.20
                               B   11  33.7    0.41     1.1    15.0             0.03
                               V               0.15     0.5    14.0             0.02
                               U   13  47.6    0.62     1.0     7.0             0.16
                               B               0.10     0.2     5.7             0.03
                               V               0.04     0.1     0.6             0.02
                               U   14  59.8    1.27
                               B               0.22
                               V   14  59.9    0.08
                               U               1.25  U  5.7    13.0             0.23
                               B   15  00.4    0.22  B  0.4    12.0             0.03
                               V    -           -    V  0.1     4.0             0.02
                               U               1.13
                               B   15 00.8     0.21
                               V    -           -

    28    11  01   - 12  14
          13  00   - 18  23


Tokyo Astronomical Observatory
31 March 1972.

                          K. OSAWA,     K. ICHIMURA,
                          Y. SHIMIZU,   E. WATANABE,
                          T. OKADA,     M. YUTANI,
                          H. KOYANO,    K. OKIDA