STRUCTURE AND KINEMATICS OF THE WIDE VICINITY OF THE ALPHA PERSEI OPEN CLUSTER

Abstract

We present the results of an investigation of the wide (approximately 100 × 100 ◦ ) vicinities of the open cluster Alpha Persei (Melotte 20) by the data of the Gaia DR2 catalog. We select two structures in this region. The first one is the cluster proper with the mass of 900 solar masses approximately and the tidal radius of 12.8 parsecs (4 . 2 ◦ ) with an extended corona with the radius of about 20 ◦ . The second one is a “stream” or the “filament” extending over 70 ◦ approximately. This “stream” is slightly farther than the cluster and overlaps with it partially. Both the cluster and the “stream” have the structural features arguing for their mutual tidal interaction. We determined the cluster rotation parameters. Different hypothesis of the “stream” origin are discussed.