COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1311

                                   Konkoly Observatory
                                   Budapest
                                   1977 July 28



     A DISTORTION WAVE IN THE LIGHT CURVE OF MM HERCULIS




   The purpose of this note is to announce the existence of a
wave-like distortion in the out-of-eclipse light curve of MM Her.
To our knowledge a wave in MM Her has not been detected before
this (Hall 1976). The most recent photometry is that of Oliver
(1974). The most recent spectroscopic study is that of Imbert
(1971).
   Using the No.3 16-inch (40-cm) Cassegrain reflector at
Kitt Peak National Observatory, Burke and Mullins obtained 45
differential UBV observations with respect to the comparison star
BD +21d3274 between J.D. 2,442,944.5 and 2,442,962.5. Using the
same comparison star, Henry obtained 69 UBV observations between
J.D.2,442,972.5 and 2,443,070.5 with the 32-inch (80-cm) 
Cassegrain reflector of the Ohio State University at Perkins 
Observatory. These observations were corrected for differential
atmospheric extinction and transformed differentially to the
UBV system. Nightly means of the V observations are plotted in
the figure where phase is computed with the ephemeris
         JD (hel.)= 2,431,302.451+7.96037d E.
There is a faint visual companion for which we estimate rho = 18
arcseconds, and theta = 120deg. A correction of +0.025m has been added
to the Kitt Peak data to allow for the fact that Burke and Mullins
included the companion in the diaphragm during photometry while
Henry excluded it. One relatively uncertain measurement of the
companion relative to the comparison star yielded DeltaV = 4.92m:.
Combined with the brightness of the comparison star, V=8.46m+-0.03m
according to Oliver (1974), this yields V=13.4 for the companion.
Inclusion of a V = 13.4m companion would increase the deflections
of MM Her outside eclipse by 0.03m, in fair agreement with the
0.025m shift we actually applied. No observations were obtained
during the relatively short (D = 10 hours) eclipses.
    A nearly sinusoidal wave approximately 0.08m in amplitude
(from max. to min.) is apparent in V. The observations in B and
U indicate amplitudes of approximately 0.07m and 0.06m, respectively. 
Wave minimum occurs at phase 0.8p. The authors are continuing 
to observe MM Her in 1977 to see if the wave exhibits any
migration in phase or variation in amplitude.




   DOUGLAS S. HALL         EDWARD W. BURKE, Jr. *
   GREGORY W. HENRY        JEFFREY L. MULLINS *
   Dyer Observatory        King College
   Vanderbilt University   Bristol, Tennessee
   Nashville, Tennessee




References:
Hall, D.S. 1976, I.A.U. Colloquium No. 29, 287 [BIBCODE 1976ASSL...60..287H ]
Imbert, M. 1971, Astr. and Astrophysics, 12, 155 [BIBCODE 1971A&A....12..155I ]
Oliver, J.P. 1974, Ph.D. Thesis, U.C.L.A.


* Visiting Astronomer, Kitt Peak National Observatory, which is
operated by the Association of Universities for Research in
Astronomy, Inc., under contract with the National Science Foundation.


                       [FIGURE 1]