COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2021

                                 Konkoly Observatory
                                 Budapest
                                 1981 September 30

                                 HU ISSN 0374-0676



       VARIABILITY IN THE WOLF-RAYET STAR HD 164270

The WC9 star HD 164270 (= WR 103 *; alpha_1950=17h58m26.4s, delta_1950=-32d42'55")
was found to decrease its brightness by almost 1.2m from June 4 to June 21
1980 (Lundstrom and Stenholm, 1981). Our observations were interrupted June
23, when the star had become ~ 0.2m brighter than its minimum value. During
this period only very minor colour changes appeared. In April 1981 the star
had returned to its normal brightness, v = 9.01, (Smith, 1968).
   There is no obvious explanation for the behaviour of HD 164270 in June
1980, although an occultation by an object with low luminosity and large
radius seems to be the most promising alternative. The interpretation is
however seriously hampered by the limited observational material available
to us.

   We are therefore very interested in all observations of this star that
might have been made in 1980, especially during the time period May to August
1980. Spectrographic observations are extremely important and even low 
dispersion objective-prism spectra might be very valuable.


*The designation WR refers to the Wolf-Rayet star catalogue by van der Hucht
et al. (1981).


                      INGEMAR LUNDSTROM
                      BJORN STENHOLM
                      Lund Observatory
                      Box 1107
                      S-221 04 LUND, Sweden


References:

van der Hucht, K.A., Conti, P.S., Lundstrom, I., Stenholm, B.: 1981, Sp. Sci.
   Rev. 28, 225 [BIBCODE 1981SSRv...28..227V ]
Lundstrom, I., Stenholm, B.: 1981, preprint [BIBCODE 1982IAUS...99..289L ]
Smith, L.F.: 1968, Monthly Notices Roy. Astron. Soc. 140, 409 [BIBCODE 1968MNRAS.140..409S ]