COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 561


                       		 Konkoly Observatory
                       		 Budapest
                    	         1971 June 9


PHOTOMETRIC OBSERVATIONS OF YZ CANIS MINORIS AND AD LEONIS

YZ CMi
      The flare star YZ Canis Minoris was monitored at
Boyden Observatory for a total tine of 10h49m during the
recent International Co-operative period from the 16th 
January to 2nd February, 1971. Unfortunately adverse weather
conditions prevented extensive observations. During the
brief runs that were possible, no flare activity was detected 
with the 40cm aperture Nishimura Reflector.


     Monitoring Table of YZ Canis Minoris
------------------------------------------------
Date                 Total Hours
1971        U.T.      per Night
------------------------------------------------
Jan
 21   20h49m- 22h26m   1h37m
 22   18 35 - 22 12    3 37   No flare activity
 25   20 59 - 21 41    0 45   observed
 27   18 31 - 23 21    4 50
              Total   10h49m
------------------------------------------------



AD Leo
      During the recent International Co-operative period
from the 18th February to 4th March, 1971, observations
were carried out from Boyden Observatory on the flare star
AD Leo. The 40cm aperture Nishimura Reflector was used with
an EMI 6256 cooled photomultiplier tube along with a
Johnson B Filter.
      The table gives details of the monitoring and it
will be seen that three low intensity flares were recorded
during the period.
      The total monitoring time was 38h52m. Flare No. 1 is
particularly interesting in that it had a relatively long
duration of 15.2m with a fairly gradual decline alter a
flash phase. This is similar in features to other long 
duration flares from AD Leo previously reported at Boyden
(A.B. Jarrett and J.P. Eksteen, 1969, 1970).



           Monitoring Table of AD Leo
-------------------------------------------------------------
                        Total
Date                    Hours   Flare   U.T.     Duration
1971       U.T.          per     No.     of      
                        Night           Flare          Deltam
-------------------------------------------------------------
Feb.               
17   19h09m- 20h40m      1h31m    1   19h54.8m  15.2m   0.21
18   19 44 - 21 45       2 01
21   18 25 - 22 28       4 03
23   18 24 - 21 35       3 11
24   18 08 - 23 08       5 00
25   18 14 - 21 29       3 15
28   18 06 - 22 14       4 59     2   19h38.0m    6.0   0.15
     22 32 - 23 23
March
 1   18 02 - 22 40       4 38     3   21 59.6     1.4   0.18
 2   18 27 - 23 16       4 49
 3   19 15 - 22 54       3 39
 4   21 21 - 23 07       1 46
              Total     38h52m
-------------------------------------------------------------
25th May, 1971.




                     A.H. JARRETT and J.P. EKSTEEN
                       Boyden Observatory,
                      Department of Astronomy,

                   University of the Orange Free State,
                    Bloemfontein Rep. of South Africa



References:
Jarrett, A.H. and Eksteen, J.P. 1969 MNASSA 28, 70. [BIBCODE 1969MNSSA..28...70J ]
Jarrett, A.H. and Eksteen, J.P. 1970 MNASSA 29, 78. [BIBCODE 1970MNSSA..29...78J ]


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