COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1866

                                   Konkoly Observatory
                                   Budapest
                                   1980 November 13

                                   HU ISSN 0374-0676




           AN INTERESTING PHENOMENON OF THE
               FLARE STAR BD+22d3406



  Continuous photoelectric monitoring of the flare star
BD+22d3406 has been carried out at Kottamia Observatory-Egypt
(lambda=31d49'30", phi=+29d55'54", H=476m) as a continuation of flare
stars' programme started at Stephanion Observatory-Greece. The
observations were made in the B-colour. The description of the
telescope and the connected equipments will be described elsewhere.
  During the photoelectric patrol observations of this flare
star, a sudden decrease of its brightness followed by increase
of its brightness have been registered. We can call this decrease 
of brightness anti-flare. The star, after the decrease
and increase in brightness has become again stable. Here we give
the parameters of the flare and anti-flare phenomenon. Table I
gives the date of observations,monitoring intervals in U.T.,total
monitoring time and the standard deviation of random noise fluctuation 
sigma(mag) = 2.5 log (I_0+sigma)/I_0 for different times (U.T,)
of the corresponding monitoring intervals.

                          Table I
                 Monitoring intervals in 1980
Date                                    Total
1980    Monitoring intervals (U.T.)    monitoring           sigma(mag)
May                                     time
25      00h42m - 01h46m                  01h04m              0.03

25-26   22 47m - 23 22m,23h24m-00h08m,                      0.04,0.08,
        00 11  - 00 35.                  01 43              0.04
27-28   22 53  - 23 14, 23 43 -00 24,                       0.00,0.20,
        00 29  - 01 08, 01 12 -01 48.    02 17              0.11,0.06
29-30   22 22  - 23 16, 23 18 -23 37,                       0.04,0.00,
        23 40  - 23 51, 23 53 -00 51,                       0.02,0.05,
        00 54  - 00 57, 00 59 -01 20.    02h46m             0.04,0.06
                                 Total   07 50

                    Table II
     Characteristics of the flares and anti-flares observed

     Flare
     Date                
No.  1980    U.T   T_b   T_a     D    I_f-I_o/I_o   P     Delta m  sigma   air
     May     max   min.  min.   min.    max.       min.     mag     mag    mass
1.A   25  01h07m20 0.20  0.10  0.30    -0.46        ^      -0.67     ^     1.03
1.B   25  01 11.72 3.20  2.10  5.30    +0.41      +2.48    +0.37    0.03   1.04
1.C   25  01 38.04 0.20  3.30  3.50    +0.55        v      +0.48     v     1.07
2.A   28  00 04.41 1.40  0.10  1.50    -0.54        ^      -0.84     ^     1.01
2.B   28  00 05.69 0.20  0.50  0.70    -0.42      -0.40    -0.59    0.02v  1.04
3.    29  22 22.48 0.40  1.30  1.70    +0.76      +0.35    +0.61    0.04   1.01

Table II gives the characteristics of each flare and anti-flare
(Andrews et al.,1969) : the date and U.T. of flare maximum and
anti-flare minimum, the duration before and after the maximum or
minimum (t_b t_a, respectively), as well as the total duration
of the flare and anti-flare (D), the value of the ratio (I_f-I_o)/I_o
corresponding to flare and anti-flare extremum, where I_o is
the intensity deflection less sky background of the quiet star
and I_f is the total intensity deflection less sky background of
the star plus flare or anti-flare, the integrated intensity of
the flare and anti-flare over its total duration, p=Integral [(I_f-I_o)/I_o]dt
the increase or decrease of the apparent magnitude of the star
at flare maximum or anti-flare minimum Delta m(b)=2.5 log(I_f/I_o),
where b is the blue magnitude of the star in the instrumental
system, the standard deviation of random noise fluctuation
sigma(mag)=2.5 log (I_o+sigma)/I_o during the quiet-state phase immediately
preceding the beginning of the flare or anti-flare, and the air
mass at flare or anti-flare,


                       [FIGURE 1]

  The light curves of the observed flares and anti-flares in
the b colour are shown in Figs. 1-3.

                       [FIGURE 2]
                       [FIGURE 3]


                               F.M. MAHMOUD, M.A. SOLIMAN
                             Helwan Institute of Astronomy and
                             Geophysics, Egypt

Reference:
Andrews, A.D., Chugainov, P.F., Gershberg, R.I., and Oskanian,
      V.S., 1969, I.B.V.S. No. 326