THE STELLAR CONTENT OF ASSOCIATIONS AND STAR COMPLEXES IN M33

A list of 289 stellar associations and 47 star complexes has been compiled. This study is based on a photographic UBV photometry carried out with the 3.6 m CFHT by W. L. Freedman and the 2 m Bulgarian telescope. The identification charts of stellar associations and star complexes are presented. The photographs reveal new appearance for associations. They are seen as clustering within the classical OB associations. The boundaries of the associations were delineated using a cluster analysis. The problems related to the age and size distribution of associations are discussed. The stellar associations provide a good observational test for shock wave across the southern spiral arm. The star complexes in the central region and in the southern spiral arm are rich in WR, O and luminous stars and poor in red supergiants while in the outer region is quite contrary. There is a brief discussion whether the different stellar content of star complexes could be explained with radial metal abundance in M33 or with variations of the luminosity function from one complex to another. M33 is compared with other nearby galaxies.