COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1114

                                  Konkoly Observatory
                                  Budapest
                                  1976 March 13



            W UMa: A NEW PERIOD VARIATION



   The behaviour of the period of W UMa is known to be subjected 
to fast and slow variations (Cester, 1969). The last one occurred 
in 1969-70 with a reduction of the period  (Cester, Pucillo
1972). Observations of some minima made in 1979 and 1975 suggested 
the possibility of a new lengthening: this was briefly communicated 
in the Bibliography on Close Binaries 25. New observations
made at the end of this February  confirm the variation, as it can
be seen from the positive residuals referred to the elements valid
since 1970: Min.I=J.D.2441004.39769+0.33363696 E. All times were
deduced after Kwee and van Woerden method.

Hel.J.D.       m.e.        O-C
2442000+

101.39680 +-0.00003      +0.00079
120.41352    .00006      +0.00020
451.38263    .00009      +0.00145
462.39281    .00005      +0.00160
830.39480    .00008      +0.00203
830.39909    .00004      +0.00132
831.39608    .00019      +0.00240
835.39900    .00005      +0.00167
835.39900    .00003      +0.00167
836.39998    .00003      +0.00174
837.40109    .00003      +0.00194
839.40306    .00008      +0.00209



                      B. CESTER, U. FLORA,
                      F. MARDIROSSIAN, M. PUCILLO
                      Osservatorio Astronomico
                      34131 Trieste - Italy


References:
Cester, B. 1969, Mem.S.A.It. 40, 489 [BIBCODE 1969MmSAI..40..489C ]
Cester, B., Pucillo, M., 1972, I.B.V.S. No. 659