Massive OB Star Clusters in Cassiopeia

Abstract

We present a new investigation of several sparse OB associations in Cassiopeia (Cas OB2, OB4, OB5, OB7, and OB8) to revisit their membership and kinematics in the Gaia era. We compare the spatial distribution of the OB associations’ members, the known OB-type stars from the Reed catalog, and candidate hot stars from the Gaia Data Release 3. We also investigate the reddening distributions across the region to further understand the kinematics of these groups relative to the region’s molecular clouds.