OB STELLAR ASSOCIATIONS IN THE DIRECTION OF CENTAURUS OB2

One hundred eighty-five mostly OB and some early A-type stars are dete cted at 1640 Angstrom with the ultraviolet telescope Glazar aboard the Mir space station in an area of about 8 deg(2) in the direction towar d the stellar association Cen OB2. The limiting stellar magnitude m(16 40) of the observations is about 8.5 mag. Stellar associations at dist ances of 360, 850, 1500, 2300, 2700, 4000, and 6700 pc are detected by the study of the space distribution of 111 of the observed stars with known spectral types. It was shown that the cluster IC 2944 is locate d at a distance of 2200 pc. It is suggested that the extinction of emi ssion of stars in the content of the cluster is due to small dust clou ds or even to circumstellar dust shells. It is shown also that the dus t matter is practically absent in the space between stellar associatio ns and that the extinction of some stars within stellar associations i s caused by relatively small dust clouds, in which the stars an embedd ed. Two of the detected stars, HD 101316 and HD 101967, are of relativ ely late spectral types and therefore probably have hot dwarf or subdw arf companions.