LAB H i  emission distribution averaged in the velocity range from –42.26 to –34.02 km   s^-1. Contour levels are from 10 to 90 in steps of 10 K. The area below the dashed line corresponds to the region where CGPS data are not available. The symbols indicate the location of the star members of Cep OB1 lying inside the ellipse (see Sect. 3.3). White star symbols correspond to O-type main-sequence stars. Asterisks and triangles indicate evolved stars that were O-type and B-type stars during the main-sequence phase, respectively.