Red Clump Giants in the Region of Open Cluster M29

The interstellar extinction is investigated in a 1.5 square degree area in the region of the open cluster M29 (NGC 6913) in Cygnus, centered at RA = 20 h 24 m, DEC = +38 deg 30 min. The study is based on the investigation of 1147 red clump giants (RCGs), identified by using some combined two-color diagrams of the 2MASS and Spitzer surveys in the region of highly variable extinction. In the whole area a steep rise of the extinction A_V is observed at a distance of ~800 pc; it should be related with dust clouds in the Great Cygnus Rift obscuring the stars behind it by A_V ~ 3.0 ± 0.5 mag. Another rise of the extinction by additional ~5 mag seems to be present at 1.3 kpc, the frontside of the CygX complex of dust and molecular clouds.