COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 735

                                 Konkoly Observatory
                                 Budapest
                                 1972 November 3

      THE PERIODS OF SIX RR LYRAE TYPE STARS



Students at the Maria Mitchell Observatory have 
obtained new or confirmed periods for six variable stars of
type RRab, as tabulated. The unnamed stars had previously
been discovered by Hoffleit.
For TX Comae, Pamela Bonnell independently found a
period of 0.536477d, differing in the last place from the
period found in the General Catalogue of Variable Stars.
The latter period also satisfies Miss Bonnell's observations 
and gives better accord between the published JD
of maximum and the one tabulated here.
Donna Henry found that either of two periods satisfies 
her observations of EL Comae on approximately  100
plates taken between 1964 and 1972, although the shorter
of the two is slightly preferred.
The final variable, in Sagittarius, was found by 
Pamela Knight to have a changing period. The phases in decimal 
parts of the period, for some 500 observations from
1924 through-1972 are well represented by the relation,

phi = 1.906186(JD - 31674.200)- n - 1.9*10^-10 n^2,

whence Max = 31674.200+ 0.524608n + 10^-10 n^2.

Miss Bonnell, a Vassar College student, worked under
NSF Grant GP 30065 in the summer of 1971. Miss Henry and
Miss Knight were NSF Undergraduate Research Participants
from Wellesley College in the summer of 1972.


28 October 1972


                       DORRIT HOFFLEIT
                   Maria Mitchell Observatory
                   Nantucket, Mass., U.S.A.



-------------------------------------------------------------------------------
Var   R.A.(1900)    Dec.    Max    Min    JD (max)    Period    Observer
-------------------------------------------------------------------------------
A      11h56m28s+ 32d27.4'  13.3   14.3   40382.627   0.61031d  D. Henry
B      12 00 51 + 28 12.6   13.7   15.8   39268.617   0.444766  D. Henry
TX Com 12 45 10 + 31 41.0   13.5   14.8   40738.633   0.536470  P. Bonnell
C      12 46 21 + 33 30.0   12.4   13.9   40022.531   0.57465   D. Henry
EL Com 12 46 35 + 24 40.1   13.8   15.0   38532.557   0.343329    or
                                                      0.52362   D. Henry
77^x   18 20 13 - 21 16.8   12.5   14.3   31674.200   0.524608+
                                                      +10^-10 n  P. Knight
-------------------------------------------------------------------------------

 x Number as in IBVS 660, 1972.


                           [FIGURE 1]

-------------------
A   1= BD +32d2211
B   1=    +28d2077
    2=        2078
    3=        2075
C   1=    +33d2278
    2=        2277
-------------------