COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 1085

                                  Konkoly Observatory
                                  Budapest
                                  1976 January 24


      STAR ON POSITION OF PKS 1925-524 VARIABLE


The radio source PKS 1925-524(alpha_1950 19h25m46s, delta_1950 -52d26'19")
was identified by Wall and Cannon (1973) with "a bright star (V~~12m)
on position". Since no finding chart was published, an identification 
was made using ESO Sky Survey print 232 of the B series  and
the accompanying overlay grids. Table 1 gives V magnitudes and colours 
for comparison stars in the finding chart (Fig. 1).


Table 1  COMPARISON STARS

Star  V      B-V     U-B
----------------------------
1   10.144   .643    .198
2   10.596  1.087    .914
3   11.833   .604    .041
5   11.695   .446    .049
8   11.262   .408   -.045
----------------------------

       UBV observations were obtained
in July 1975 with the 61 cm telescope
of Bochum University located on La
Silla. A description of this telescope
and photometric equipment has been
made by Schmidt-Kaler and Dachs (1968).
A second set of UBV measurements was                
                                                     [FIGURE 1]
made two months later with the 61 cm
telescope of the University of Toronto
located on Las Campanas (Carnegie
Southern Observatory).

                                             Fig. 1. Finding chart for PKS
                                             1925-524 (vertical bars)
                                             showing comparison stars.
 All observations were made with
star 8 as comparison and stars 2,3
and 5 used as a check. Initial observations 
were mainly in B, so that this set of data was used for  a
period determination. The combined observations in instrumental  b
magnitudes are shown in Fig. 2  assuming a period of 0.59064d +- 0001.

                     [FIGURE 2]

  Fig. 2  Combined observations in instrumental b magnitudes
  using star 8 as comparison

This period was derived using the method of Lafler and Kinman
(1965). For secondary minimum the epoch is HJD 2492621.77477.
    The mean range is 11.08 - 11.45 (B) with a secondary 
minimum at 11.35. The mean B-V remains virtually unchanged when
going through secondary minimum; mean B-V at normal light is
+.386 and +.384 in secondary minimum. At primary minimum B-V is
about +.46, though this is based on rather limited data.
    Several image tube spectra were obtained at 86 A/mm with
the 1.52 m telescope on La Silla. These, and additional ones
with the 61 cm telescope on Las Campanas at 112 A/mm, indicate
a spectral type of late F. Tracings of the H_beta absorption profile
show rapid variations of possibly suppressed emission. One hour
of H_beta photometry also shows these fluctuations on a short time
scale (~5 minutes).
    It would seem that these data are indicative of a W UMa
system. Further spectroscopic and photometric observations are
planned for the coming year.


                          C. J. SMITH
                     European Southern Observatory
                      Casilla 16317, Santiago 9
                            Chile



References:

J. Lafler, T.D. Kinman, Astrophys.Journ. Suppl. 11, 216, 1965. [BIBCODE 1965ApJS...11..216L ]
T. Schmidt-Kaler, J. Dachs, ESO Bull. No 5, p. 15, 1968.
J.V. Wall, R.D. Cannon,  Australian Journ. Phys. Astrophys.Suppl.
                           31, 1973.  [BIBCODE 1973AuJPA..31....1W ]