European scientists found 42 new massive members in the star association Cygnus OB2. This territory is 4800 light-years distant from us and is the richest stellar association of spectral classes O and B. It is connected with one of the most powerful regions of stellar birth, the Cygnus complex.
Swan OB2 demonstrates a large homogeneous population of OM stars that can be analyzed. Previously conducted many studies, but a complete census of objects has not yet been completed.
This was decided to fix by scientists from Germany and Spain. Sarah Rodriguez Group in 2013-2017 organized a spectroscopic observational campaign in Cygnus OB2. They considered more than 60 applicants and calculated 42 OB-type objects.
Spitzer fixed the area in Cygnus, demonstrating 61 OB-type candidates. The red dots mark 42 confirmed massive OB-type stars, and the green dots mark the late B-type and closer A-F-G. The circle of the solid line is a plot with a radius of 1 degree It turned out that the 30 stars found belong to the spectral types B0 and B1, and only one - B2. The remaining 11 belong to the O-type, one - O6, and the rest - O7 to O9. Another 19 applicants were ranked as types A, F, and G. It is important to note that 16 of the 42 objects found were recorded in the association OB2, the rest were around it.
The two stars J20272099 + 4121262 and HD228973 are of double type. There is also the possibility that 7 more stars are binary, but confirmation is required. The hottest is J20423509 + 4256364 (38192 K), and the brightest is J20395358 + 4222506.
Despite the discovery of a huge number of new stars in the association Swan OB2, it will take more time to complete the census.
