COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 1377

                                  Konkoly Observatory
                                  Budapest
                                  1978 January 3




             PHOTOMETRY OF HD 193793



    Williams, Stewart, Beattie, and Lee (1977) have recently
drawn attention to the Wolf-Rayet star HD 193793. Their photometry 
in the J, H, K, and L bands has indicated that the star
has brightened by about two magnitudes in the near-infrared, and
they suggest that an optically thick dust shell has formed 
around the star. If this were so it should also be apparent in
the visible spectral region, and since Demers and Fernie (1964)
had earlier obtained UBV photometry of the star, it seemed 
worthwhile to repeat this photometry now.
    UBVRI observations were obtained on the night of October
17/18, 1977 (JD 2443434.575) with the 0.6-metre telescope of
the David Dunlap Observatory. The results, together with the
earlier photometry are as follows:

                      1977   1964
              V:      6.87   6.86
             U-B :   -0.29  -0.31
             B-V:     0.41   0.42
             V-R:     0.54    -
             V-I:     0.81    -

Although the present observations were made on only one night,
they are thought to be accurate to about 0.01 or 0.02 mag. In
any case, the differences between the present and earlier 
observations are not significant and do not support the suggestion
of an optically thick dust shell.


                           J.D. FERNIE

                           David Dunlap Observatory
                           Richmond Hill, Ontario
                           Canada

References:
Demers S. and Fernie, J.D. 1964, P.A.S.P. 76, 350   [BIBCODE 1964PASP...76..350D ]
Williams, P.M., Stewart  M.J., Beattie D.H., and Lee T.J. 1977
         I.A.U. Circular, No. 3107 [BIBCODE 1977IAUC.3107....2W ]