COMMISSION 27 OF THE I.A.U.
                INFORMATION BULLETIN ON VARIABLE STARS
                             Number 1236

                                                       Konkoly Observatory
                                                       Budapest
                                                       1977 February 10


      1976 PHOTOELECTRIC PHOTOMETRY OF lambda ANDROMEDAE

Lambda And, a one-lined spectroscopic binary of orbital period 20.52d, 
displays a number of the properties of the RS CVn-type binaries (Hall 1976).
Among these are late spectral type (G8 IV-III), H and K emission (Herbst
1973), a quasi-sinusoidal light variability (Archer 1960), and radio
emission (Bath 1976). It differs from the RS CVn binaries in that the
period of light variability is very different from the orbital period:
~50d versus ~20d.
   On 45 different nights between 2,443, 027.5 and 2,443, 122.5 we made
a total of 135 differential photoelectric observations of Lambda And in the
visual wavelength region, all of us using 1P21 photomultipliers and using
Psi And as the comparison star. At Landis Observatory, 24 observations were
made with the 8-inch (20-cm); at Hickox Observatory, 83 with the 10-inch
(25-cm); at Dyer Observatory, 28 with the 24-inch (60-cm). Nightly means
of these observations, corrected for atmospheric extinction and transformed
to V of the UBV system, are presented graphically in the figure.

                          [FIGURE 1]

   The interval between the two rising branches, measured at DeltaV = 1.1, is
52 d; the interval between the two falling branches is 55 d. Maxima occurred
at approximately 2,443,045 and 2,443,100; minimum occurred at approximately
2,443,073; the amplitude in V is about 0.25m, whereas Archer found it to
vary between 0.19m and 0.35m in the photographic. Our two maxima appear to
differ by about 0.03m.
   The data in Table IV of Archer show that successive maxima occur at
intervals which range between 48 and 57 days and average about 51 days. 
Because of this range, which appears to be intrinsic rather than a result of
observational uncertainty, proper count of the integral number of elapsed
cycles cannot be maintained over intervals longer than about one year. Gaps
of up to 22 years exist in Archer's Table IV. For this reason it would seem
that the O-C curve in Archer's Figure 5 is not a meaningful representation
of the long-term behavior of the light variation and that the value 55.82,
is of no particular significance. Our own photoelectric observations and
those of Archer are separated by 18 years and therefore probably can never
be phased together properly.


          HOWARD J. LANDIS         LARRY P. LOVELL

         Landis Observatory       Hickox Observatory
         East Point, Georgia      Chagrin Falls, Ohio


                         DOUGLAS S. HALL
                         ROBERT W. KELLEY

                         Dyer Observatory
                         Vanderbilt University
                         Nashville, Tennessee



References:

Archer, S., 1960, J.B.A.A., 70, 95.
Bath, G. T., 1976, private communication.
Hall, D. S., 1976, I.A.U. Colloquium No. 29, in press. [BIBCODE 1976ASSL...60..287H ]
Herbst, W., 1973, Astr. Astrophys. 26, 137. [BIBCODE 1973A&A....26..137H ]