COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 441

                                Konkoly Observatory
                                Budapest
                                1970 June 29


      PHOTOELECTRIC OBSERVATIONS OF FLARE STARS

      YZ CMi, AD Leo and BD +13 2618 were monitored photoelectrically 
with the 64-cm meniscus telescope of the
Crimean Astrophysical Observatory during (and partly outside) 
the periods of cooperative observations in 1970. The
photometric system was the same (similar to B) as in our
previous observations. The dates and UT of coverage are
given in Table I. Table II contains the following characteristics 
of flares: moments of maxima (UT); durations of
flares before and after maxima, t_b and t_a (in minutes);
amplitudes of flares delta m_B in stellar magnitudes; the limiting
amplitude of a flare delta m lim which could be detected; integrated 
intensities P (in minutes); and the air masses
M(z). The detailed description of the manner in which these
characteristics should be obtained was given earlier (1),
The light curves of flares in relative intensities are given
on the figures. Table I


                                                        Table 1
Date                                            
1970                UT of coverage

                        YZ CMi
Febr 8          1710-1913

                        AD Leo
March 2         2028-2138, 2140-2203, 2210-2217, 2223-2231,
                2233-2247, 2249-2255, 2303-2306, 2310-2317, 
                2332-2338, 2346-2357, 2359-0000
March 3         0000-0009, 0013-0045, 0048-0130, 0133-0143
March 4         1707-1816, 1818-1830
March 7         1805-1817, 1841-1911, 1916-1930, 1932-1950,
                2009-2304, 2307-2311, 2321-2332, 2343-0000
March 8         0000-0200, 1809-1830, 2217-2250, 2302-2315, 
                2326-2346
March 10        1700-1715, 1730-1747, 1752-1812, 1824-1846,
                1847-1900, 1903-1916
March 12        1654-1753, 1801-1945, 1959-2019, 2031-2038,
                2048-2218, 2339-0000
March 13        0000-0014

                        BD +13 2618
March 31        1847-2017, 2035-2045, 2052-2131, 2132-2231,
                2233-2344
April 1         0002-0024, 0025-0045, 0050-0100
April 9         1855-1907, 1909-2024, 2027-2101, 2103-2130,
                2132-2152, 2202-2217, 2223-2347, 2355-2402
April 10        0004-0047, 2104-2146, 2230-2300
April 21        1836-1931, 1936-2023, 2030-2315
April 25        1832-1941, 1944-2002, 2004-2132, 2135-2232
April 26        1854-1942, 2019-2054
April 27        2230-2242, 2244-2349, 2357-2416
April 28        0028-0047, 0055-0102, 1845-1905, 1928-2130,
                2219-2238, 2240-2311, 2325-2335, 2339-2447
April 29        0053-0101



                                                Table 2

Date and UT
 of flare         t_b     t_a     delta m_B   delta m_lim     P    M(z)
 maximum

Febr 8   18 33.7  1.0      36      1.25         0.06        10.8   1.5
March 2  20 55.0  10:      65     >0.75         0.05       >316    1.1
      7  20 48.5  0.7      2.7     0.06         0.04        0.09   1.1
      7  21 04.9  0.7      2.1     0.10         0.04        0.09   1.1
      7  21 29.8  1.2      5.2     0.08         0.04        0.28   1.1
      7  21 57.6  0.2      7.6     0.12         0.04        0.40   1.1
      7  22 48.8  0.2      3.7     0.20         0.04        0.17   1.2
      8  00 10.8  0.2      0.4     0.12         0.04        0.04   1.5
     12  18 49.3  0.5      1.7     0.13         0.04        0.11   1.1
     12  19 27.5  0.7      3.5     0.09         0.04        0.14   1.1
April 9  21 43.0  1.0      6.0     0.11         0.03        0.25   1.2
     10  01 02.8  0.1      0.2     0.13         0.03        0.02   1.3

                         [FIGURE 1]
                         [FIGURE 2]
                         [FIGURE 3]
                         [FIGURE 4]
                         [FIGURE 5]


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



[REFERENCES]
(1) A.D. Andrews, P.F. Chugainov, R.E. Gershberg, V.S. Oskanjan,
   IBVS No. 326, 1969.