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Apex determination and detection of stellar clumps in the open cluster M 67

We determined the cluster apex coordinates, studied the substructures and performed membership analysis in the central part (34'X33') of the open cluster M 67. We used the individual stellar apexes method developed earlier and classical technique of proper motion diagrams in coordinate system connected with apex. The neighbour-to-neighbour distance technique was applied to detect space details. The membership list was corrected and some stars were excluded from the most probable members list. The apex coordinates have been determined as: A0=132.97deg+/-0.81deg and D0=11.85deg+/-0.90deg. The 2D-space star density field was analysed and high degree of inhomogeneity was found.