COMMISSION 27 OF THE I. A. U.
               INFORMATION BULLETIN ON VARIABLE STARS
                          Number 2564

                                            Konkoly Observatory
                                            Budapest
                                            30 July 1984

                                            HU ISSN 0374-0676


                  PERIOD VARIATIONS OF SS Ari

  SS Ari (BD +23d 279) is an eclipsing binary of W UMa-type. The new 
photoelectric observations of this system were carried out in October, 1982.
single channel photometer attached to the 60 cm reflector of the Ostrowik
Station of the Warsaw University Observatory was used. Based on our observations
we calculated three individual times of minima. They were determined
with the method of Kwee and Van Woerden (1956) and are given below:

  JD Hel        Sigma             Colour
2445261.3843   0.0002    Min II     V
       .3856   0.0005               B
2445261.5859   0.0002    Min  I     V
       .5861   0.0004               B
2445262.3992   0.0003    Min  I     V
       .3982   0.0003               B

Figure 1 shows the O-C diagram. It is based on the data available in literature.


                                [FIGURE 1]


The crosses denote photoelectric times of minima, the dots visual or 
photographic ones. The minimum at E = -33 304 is a mean value from 12 visual minima.
The O-C deviations were calculated using the ephemeris:

         HJD Min I = 2444469.5060 + 0.40599174d E

  One can see that the O-C diagram has a sine-like shape. This suggests a
presence of a third body in the system. However basing on the available data
we cannot rule out a possibility that the period variations of SS Ari are
not continuous. The abrupt character of changes of the period is typical for
most W UMa-type systems.
  Future determinations of the times of minima of SS Ari would be useful.
The detailed analysis of the light curves of SS Ari will be published in
Acta Astronomica.


              J. KALUZNY and G. POJMANSKI
              Warsaw University Observatory
              Al. Ujazdowskie 4
              00-478 Warszawa,
              POLAND