COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2438

                                          Konkoly Observatory
                                          Budapest
                                          30 November 1983

                                          HU ISSN 0374-0676



         PERIODIC LIGHT VARIABILITY OF PG1711+336



  PG1711+336, a cataclysmic variable candidate, is identified on the print
given in the paper by Green et al. (1982), where it is stated that weak 
hydrogen emissions have been observed in the spectrum of this object.
  250 brightness estimates on the plates of the Sternberg Institute's collection
(J.D. 2417823-45470) show slow variation in the range 12.5-13.2 B. The
following table gives the limits of brightness variations for some time 
intervals.


Interval
of JD24...        B         n
-----------------------------
17823-19626   12.9-13.1    15
40062-40065   12.5-12.7    10
40387-41547   12.6-12.8   210
45357-45470   13.1-13.2     5
-----------------------------

  During 1983 pulse-counting photoelectric photometers with a 48 cm reflector
and with a 60 cm reflector were used and 49 WBVR measurements* and 35 UBV
measurements (J.D. 2445442-546) were obtained, respectively. Positions of the
variable (dots) and of a number of neighbouring stars (open circles) are shown
in the two-colour (W-B, B-V) diagram (Fig. 1.). It is obvious that the 
interstellar reddening is small (E_B-V does not exceed 0.1m). Hence, the object 
has a strong ultraviolet excess, its position in the diagram corresponds 
to the position of very hot cataclysmic stars.
  The period analysis of our photoelectric observations shows that all of
them satisfy the following elements:

      JD_Min_hel = 2445527.283+0.115883d*E.

The mean V light curve plotted with this period (P_1) is shown in Figure 2.
The colour indices do not depend obviously on the phase. The dispersion of


* W-magnitudes have a response curve similar to that described by Straizys
  (1977).


                            [FIGURE 1]
                            [FIGURE 2]


data points about the mean curve exceeds the observational inaccuracies and
is due to instabilities of the light curve. One should note that another
value of the period, P_2 = 0.131117d (1/P_1-1/P_2 = 1d^-1), also gives a 
satisfactory light curve with somewhat greater dispersion of data points about
the mean curve.
  The light curve we obtained is probably due to the orbital motion in a
close binary system which is typical of dwarf novae and other cataclysmic
variables. One can see that eclipses are not observed, and the variations
are caused by the reflection effect or by a partial eclipse of the gaseous
accretion stream falling on the compact component.
  Summarizing,our observations confirm that the object belongs to cataclysmic
stars. One should, however, note that no bursts characteristic of the majority
of cataclysmic stars were observed in PG1711+335.
  To clarify the nature of this object and to find definitely which of the
period values, P_1 or 2P_1 = 0.232766d is the orbital one, further 
spectroscopic and photoelectric observations are necessary.





                  Tian-Shan Observatory of the
A.V. MIRONOV      State Sternberg Astronomical Institute
V.G. MOSHKALEV    and
S. Yu. SHUGAROV   State Sternberg Astronomical Institute
                  University of Moscow
                  13, Universitetskij Prospect
                  Moscow 117234 USSR





References:
Green R.F., Ferguson D., Liebert J., Schmidt M., 1982: Publ.Astr.Soc.Pacific
   94, 560 [BIBCODE 1982PASP...94..560G ]
Straizys V., 1977: Multicolor Stellar Photometry, Mokslas Publishers, Vilnius [BIBCODE 1977mspp.book.....S ]