COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 1251

                                                    Konkoly Observatory
                                                    Budapest
                                                    1977 March 17


     PHOTOMETRY OF RW Tri SIMULTANEOUSLY IN TWO COLORS

Photoelectric observations of RW Tri were made on the night
of November 16, 1976 with the Pennsylvania State University 60
inch reflector, simultaneously with Johnson and Morgan yellow
and blue filters. The apparent magnitude of the system in yellow
and the difference in blue and yellow are given in the Figure
for about 1.15 cycles. From observations of Walker (1963) the
system is judged to be in its faint, quiescent state.
   Noteworthy features include a total eclipse with duration of
about nine minutes and a system reddening at primary of about
0.8m. This property has not been observed before in RW Tri or
other nova associated systems such as DQ Her and UX UMa.
   From observations of RW Tri on November 15 and 16, 1976 the
period was found to be 5h33.5m, the same as determined by Walker.
Since the system may not eclipse centrally, consideration of
external and internal contact times indicate k is near the value 
of but more than 0.62. This is also consistent with the 
results obtained from analyzing the more normal, descending branch
with the psi^oc functions of Merrill (1950) for 0.6 limb darkening.
   No readily recognizable secondary minimum has been observed
yet for RW Tri. The decrease in brightness around phase 0.5 in
the displayed light curve requires qualification before it can
be designated as a secondary.


                                        L. WINKLER

                                   Department of Astronomy
                                   Pennsylvania State University
                                   University Park, Pa.16802, USA



References:

Merrill, J.E. 1950, Contr. Princeton U. Obs., No. 23 [BIBCODE 1950QB4.P94n23..... ]
Walker, M.F. 1963, Ap. J., 137, 485 [BIBCODE 1963ApJ...137..485W ]


                          [FIGURE 1]