COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1692

                                   Konkoly Observatory
                                   Budapest
                                   1979 October 19




           PHOTOELECTRIC OBSERVATIONS OF WW DRA



   The RS CVn-type eclipsing binary WW Dra (=HD150708A=BD+60d1691A=ADS
10152A) is the brighter component of the visual binary ADS 10152. Joy (1941)
and Popper (1967) derived spectroscopic elements, whereas Plaut (1940) 
obtained a photographic lightcurve. Eggen (1963) measured the UBV magnitudes
of WW Dra and of its visual companion; but no photoelectric lightcurve is
as yet available in the literature.
   Photoelectric observations of WW Dra were made by us on 7 nights in
1975 with the 50 cm Newtonian telescope of the Astronomical Observatory of
Trieste and on 20 nights in 1976 with the 30 cm Cassegrain telescope of the
same Observatory. Both telescopes were equipped with a photoelectric 
photometer bearing filters very close to the B and V standard system. BD+61d1595
was used as comparison star and was connected with the check stars BD+58d1645
BD+60d1682, BD+61d1600, and BD+63d1281. ADS 10152B, distant about 18" from
the eclipsing pair, was always measured together with WW Dra. Our measures
were not transformed to the B and V standard magnitudes, though they are
expected to be close to them. The extra-atmospheric magnitude differences
(variable minus comparison) were obtained by applying the extinction 
corrections.


                          [FIGURE 1]
                          [FIGURE 2]

   Figs. 1 and 2 show our yellow (Delta v) and blue (Delta b) observations
(obtained in 1976), phased by means of Plaut's (1940) ephemeris.
   Though coverage of the lightcurves of WW Dra at various phases is not
very good, some general charasteristics may be pointed out. The lightcurves
characterized by two minima of quite unequal depth, show cycle-to-cycle
intrinsic variations and appreciable asymmetry in the maxima. These 
photometric disturbances are common to the RS CVn-type binaries. The position
of the ascending and descending branches of the primary eclipse shows a
small displacement of the minimum from phase zero (about 0.03 in phase 
units). The secondary eclipse, though poorly delineated, seems to be 
displaced from phase 0.5 by a larger phase shift. An attempt at searching 
for a photometric solution of our data will be presented in a forthcoming 
paper.


                    M. MEZZETTI, F. PREDOLIN, B. CESTER,
                      G. GIURICIN, F. MARDIROSSIAN

                  Osservatorio Astronomico di Trieste, Italy





References:
Eggen, O.J., 1963, Astron.J. 68, 483. [BIBCODE 1963AJ.....68..483E ]
Joy, A.H., 1941, Astrophys.J. 94, 407. [BIBCODE 1941ApJ....94..407J ]
Plaut, L., 1940, Bull.Astron.Inst.Neth. 9, 121. [BIBCODE 1940BAN.....9..121P ]
Popper, D.M., 1967, Astron.J. 72, 316. [BIBCODE 1967AJ.....72Q.316P ]