COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 350



                                 Konkoly Observatory
                                 Budapest
                                 1969 May 13


      PERIODS OF VARIABLES 5 AND 9 IN M13


      Variables 5 and 9 (notation from Sawyer, 1955) in
the globular cluster M13 = NGC 6205 have been investigated
utilizing 57 recent plates taken on the Yale one-meter and
U.S. Naval Observatory 1.5 meter reflectors. The following
characteristics for the stars have been obtained (photographic
magnitude and heliocentric dates are used):

  Var  Max.  Min.    Epoch          Period    Class
   5   14.6  15.3  2440046.7820    0.381793d   RRc
   9   14.6  15.3  2440038.8121    0.392713d   RRc


      The period derived for Variable 5 also fits the
seven old observations by Shapley (1915) but fails to fit
those of Kollnig-Schattschneider (1942). However, the 
Kollnig-Schattschneider observations fit reasonably well the
period of Variable 9. Since the two stars form a close
double (separation 2.5") and at the time she made her 
observations, Kollnig-Schattschneider did not know that both
components are varying, it appears that her observations
actually refer to the second star and were misidentified.
Details of this investigation will be published elsewhere.



5 May 1969
                          WAYNE OSBORN
                      Yale University Observatory



Kollnig-Schattschneider, E. 1942. Astr. Nach. 273, 145. [BIBCODE 1942AN....273..145K ]
Sawyer, H. B. 1955. Publ. David Dunlap Obs. 1, 179.
Shapley, H. 1915. Mt. Wilson Contr. 6, 301 (No. 116).

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